Do you seriously not understand that walking away and saying nothing to an idiot does not imply that you respect their opinion? You’re talking about two completely unrelated things. You can think someone has idiotic viewpoints without crowing to the world that you think they have idiotic viewpoints. You can think someone has idiotic viewpoints without telling THEM that you think they have idiotic viewpoints. Silence != agreement.
OP: You seem to think that the only options are either a) not calling the person out, thereby strongly implying that you respect their opinion; or b) calling them out publicly, thereby proving to everyone in earshot that you are rude.
Most other people in this thread seem to see a third option, which I will articulate so:
How about doing what you apparently wish the other person would do, which is to keep your stupid opinions to yourself?
Roddy
Jane, you ignorant slut!
Of course, if the person you are calling an idiot using that line is not named Jane, then there might be a problem.
There is an underlying issue here with walking away. It’s been my experience that many folks today that walking away is wrong. It may be the better part of valor but they don’t get it. They’ve been raised in a confrontational world. They are used to getting into your face. In short, they enjoy the public insult retort because they themselves have no manners anyway, nor their friends.
Are you seriously suggesting that refusing to denounce him as an asshole in public automatically means that you respect his opinion?
That’s an interesting point of view.
I think you’ve spent too much time online with people who fit the GIFT.
Magic player?
In some Magic player circles, calling a person an idiot might qualify as being soft. 
I’d just smile, murmur “Well, bless your heart.” Then walk away…
Perfect.
“I’ve never heard of that before…” 
So just because someone has some silly unsupportable ideas, that automatically makes them an asshole? Really? Even if they’re kind and generous and have personally helped you out in the past?
Using my wizard-like powers to resurrect this zombie…
I really had to put this to the test a few days ago. I was hanging out with some great friends the other day, and the conversation turned very woo. They were trying to convince me that they’re both psychics and that psychic powers are real and there’s plenty of evidence to be had on “scientific” TV shows, and on and on and on.
I immediately thought of this thread.
What should I have done? I didn’t want to call them assholes, because they’re not. I didn’t want to alienate them, because I was depending on them for a ride and we were in the middle of nowhere. But I didn’t want to buy into their woo.
They challenged me to explain, in terms of pure science, how some observed psychic phenomenon that they saw on TV could possibly work if supernatural forces were not in play.
I think that they expected me to fumble and falter until I had to admit defeat.
“Explain that!”
“I can’t and I don’t feel obligated to do so.”
Seriously, it was a debate that I wanted no part of. I feel no need to be on the defensive against the woo.
But oh, the smug and satisfied looks they had on their faces.
I’m currently debating calling some people idiots on Facebook. They are of the opinion that Justin Bieber is on par with Leonard Cohen. To me, this is like comparing a toddler’s fingerpainting to a Picasso. In fairness to Bieber, I think he has talent but that it is being squandered by a record company pushing him to put out music that appeals mostly to 14 year old girls.
On the other hand, its Facebook so who gives a shit…
Half-joking here, but I thought one wasn’t supposed to suffer fools lightly?
suffer fools gladly.
But I don’t think it’s an admonition. These days it is usually used to describe a (usually brusque) character trait.
That’s when you have to employ the wonderful flexibility of the English language. Just say:
“Oh, wow, that’s incredible/fantastic/exceptional/terrific!” (whichever fits best)
I have a fond memory of employing these and other useful dual-use adjectives once against someone who was just spouting endless bullshit. Another cow-orker who was there knew exactly what I was doing, and we were both about dying of laughter on the inside - the bullshitter never had a clue, and thought we were just buying it all. He didn’t get all offended and argumentative, and we were greatly entertained. Now that’s a win/win!
It’s amazing how many adjectives can be used this way. In fact, I kind of wish more people around here would sometimes employ this technique on certain kinds of trolls.