An amusing image of… Christians being fed to lions? 
I think there’s a big difference between “Christians” and “Religious Right”. I have no reservations about attacking the Religious Right (which I take to mean people who want to force their religious views on the entire world), but to attack all Christians is misguided.
I’m a fairly regularly church-goin’ Episcopalian gal. I think that bumpersticker is pretty damn funny.
It does seem like a quaint and Biblical way to die. Not that I know anything about the Bible…
It doesn’t matter what a bumper sticker says, most of them are not to be taken completely literally, and most should not be taken offence to.
Now that is a bumper sticker I’d use.
I can’t speak for others but I seperate spirituality from religion. I consider myself highly spiritual while I almost universally loathe religions. To me, once something has been codified and regimented (like all religions) it ceases to be spiritual. In fact, Spirituality implies thinking about ones unique connection to the universe. Religion implies turning off the brain and letting someone else think for you. To use my favorite quote…
“Of course people want rules. Where there are rules, thought is unnecessary.” —Prof. De La Platz in Robert Heinleins “The Moon is a Harsh Mistress”.
Ahh… I’ll stop now before this hijack goes any further astray…
Regarding the OP, No I don’t think it’s offensive, but then I make fun of all religions equally.
I’d call it highly offensive.
Sorry to Godwinize but I really don’t see a whole lot of difference between that and
“So many Jews, too little Zyclon B”
Yeah there’s 2000 years removed, but still a very assholish statement.
I’m a Christian, and I’m not particularly offended by “So Many Christians, So Few Lions.” Surely the person who displays this statement doesn’t really believe that all Christians should be killed. This reminds me of the anti-Bush bumper sticker that says “Lee Harvey Oswald, Where Are You Now That We Need You?” It’s hyperbole. Sure, it’s in questionable taste. But it is funny, in a sick-joke kind of way.
Not only is it not offensive to me, it’s downright funny. First of all, I’m a big fan of offending the easily offended on the grounds that the only reason they’re offended is because they take themselves too seriously. That can only lead to a life of misery. But more importantly, the religious right is working so hard to undermine our freedoms and turn my country, which I love, into a theocracy, that I feel they’re personally attacking me. A bumper sticker like that isn’t going to stop the religious right from attempting a coup, but it does accomplish a few things: it lets others who agree with me know that they’re not alone (which is significant here in semi-rural Florida, where pro-Bush/pro-Jesus propaganda abounds), it annoys the Jesus-freaks, and lets them know that people like me aren’t going to sit back and let them trample our rights as Americans. And it shows that we’re not going to keep our mouths shut just because they might get offended. This is a fight - they made it one - and a lot more is at stake than people’s feelings.
I don’t have that particular bumper sticker on my vehicle, but I do have two others: “Keep your religion out of my government” and “Pro America/Anti Bush.”
Why not “Keep your religion out of our government”? 
There’s a world of difference. The Holocaust happened less than a century ago, and is still fresh on everyone’s mind. By the same token, a comment like “So many Blasphemers, so few stonings” doesn’t quite work as a joke because stoning remains a common form of execution in certain lesser-developed countries.
However, nobody’s fed anybody to the lions in the last 1600 years. (Well, maybe in Goodfellas.) In adition, Xtianity has blossomed from an offshoot Jewish cult to THE dominant, majority religion in the Western world, and Xtian leaders have used their religion as an excuse to torture, punish, and even destroy other cultures, from the Crusades to manifest destiny to the Bush Administration.
You gotta be careful about pissing off the Christians, though – they’ll go ballistic over any little thing (motes-in-the-eye notwithstanding) and it’s not always predictable what will draw their wrath. I used to run a music review website and the comment that drew the largest amount of hate mail, by FAR, was in a Stryper review. While discussing their one mainstream album (the one where they dropped the bumblebee outfits and the overt Christian message) I said offhand, “Satan apparently claimed their souls in the end.” Ok, maybe I was trolling for negative remarks 
(but it still far outweighed the second biggest hate-mail getter, which was that Def Leppard drum solos aren’t too spectacular these days.)
Oops, forgot to add…I’d never put an anti-Christian bumper sticker on my car because, frankly, it’s a lot more likely that my car would get vandalized. Seriously, I’ve known people who had to quit putting “Darwin Fish” on their cars because they kept getting torn off. If I were to make an anti-religious statement it would have to be something obscure like “REMEMBER THE AMALEKS!” because at least no one would know what the hell I’m talking about. 
You have a valid point- in an effort not to overuse words like “Christian” or “Religion”, I substituted a word (spirituality) that is not particularly synonomous. Having said that, statements which imply that religion implies not thinking, while individual spirituality is good rubs me the wrong way.
[What can I say? I attend a mainstream church and always have. I like traditional hymns and a hint of ritual and liturgy. Being told that this is akin to allowing someone else to think for me is annoying and untrue. It may be true for others, it is not true for me.]
It doesn’t look to me as if most of the Christian-bashers in this thread (including you) are being “careful about pissing off the Christians.” I am often amazed and appalled to see how freely folks toss around insults and snide comments directed at Christians when they know that Christians are participating in a thread.
I guess I’m just proving your point by “going ballistic over any little thing,” eh?
I don’t put bumper stickers on my car. I don’t force my beliefs on anyone, including through my bumper.
That’d make a good bumper sticker. 
Actually, in Australia you just don’t see bumper stickers. Haven’t for twenty years or so. The only exception is the typical retired couple who have a camper, and they drive around Australia collecting souvenir ones and plastering the entire back with it. Apart from that, they are pretty rare.
IANAJ but, as I understand it, in jewish law a person that is guilty of the same sin cannot morally cast a stone. So in this case He would be saying any of you that havn’t commited adultery be my guest. Appearently adultery was quite common at that time.
Maybe you could look at it as meaning Christians need forgiving other’s don’t.
Monavis
That’s horribly offensive, and intolerant and…bloodthirsty…and <giggle> … totally wrong and we… <giggle> OK where do I order one?
I too find it funny, but I can see why it is probably offensive to some Christians.
I think what makes it different from and less offensive than imaginary bumper stickers like “So many Jews, so little Zyklon B” is that Jews, Wiccans, etc. don’t go around being obnoxious about their religion. Those stickers would be motivated by pure hate and ignorance, and someone who would put a sentiment like that on their bumper probably means it literally–they don’t have a problem with violence against those groups.
But most people realize that this sticker is just meant as a joke and is a reaction to how some Christians are shoving their religion down the throats of the rest of us these days. Nobody really thinks the driver wants to kill Christians, and s/he probably doesn’t. The message is, “I’m so tired of listening to their crap,” and we all understand that that is the message.
I know some very religious Christians who think that sticker is a just a laff riot.