At least the vegetarians and animal rights folks over here: http://www.veggieboards.com/boards/:
I was banned just for not being vegetarian. I couldn’t even attempt to debate them. At least the commies at RevLeft restricted me not ban me outright.
Some places are not for debate, but for like-minded people to gather together. The front page of the board, the page you linked to, says:
You knew their rule going in, why are you surprised?
My objection to the rule was my point. They refuse to allow in people who having differing views or even non-vegetarians who like vegetarian dishes.
I’ve never heard of that site before, but are there rules about who can join? Is ther, for example, a line on the main page saying something like:
“Please keep in mind, this is not just a vegetarian forum, this is a forum for vegetarians. In order to join you must either be a vegetarian or seriously considering going vegetarian.”
And, did you drop into a thread just to say you weren’t vegetarian and see how they’d react?
Whatever.
The very front page of their forum says:
Personally, i think it’s sort of a silly rule, but it’s their forum and they make very clear what the conditions are.
It could be that they’re simply not interested in debating their vegetarianism with people who are intent on talking them out of it, or who want to question their choices.
Sucks to be you, then. They state their rules up front and clearly. Go find a more inclusive veggie board.
ETA: Oh, and if you try to turn this into some flag-wrapping free speech bullshit, the laughter will be deafening.
Okay. Well. If you just like vegetarian dishes, then lie about it. They don’t need to know you’re not vegetarian. Or, if you can’t lie, at least don’t mention that you aren’t.
If you went there trying to debate, despite the fact that that’s not the purpose of the board, you’re being a jerk. They are not obligated to allow you to do so. And, honestly, it sounds like you were trying to stir shit up.
KAYFABE!
I happen to enjoy that part.
I can’t believe nobody has pointed out this line from the front page to the OP:
Dude - not pitworthy. It’s not like veggieboards.com=Augusta Country Club.
They told you upfront by way of their membership policy: they don’t want folks pissing in their sandbox. Then you stood right up and said: “But what if I really wanna piss in your sandbox?” And you’re shocked that they kicked you out of the sandbox?
It’s like this: I’m an atheist, but I’m not going to go to catholics-only-if-you-arent-catholic-please-dont-join.com and try to debate the finer points of their membership policies.
They do have an exception: You can post as long as you’re playing Rio, by Duran Duran.
I agree that they probably just want a place for loving and togetherness without worrying about getting bombarded with antagonism. Imagine if you went to a Local Republicans Club meeting or something, and in the midst of sharing stories about how everyone has made a poor person suffer today, in storms some unwashed hippie yelling about totalitarianism or the bill of rights or some nonsense.
Not that every vegetarian should be immune from defending his stupid beliefs, but a group of people should be able to meet and discus how meat causes cancer in peace. Unless it’s a hate or intolerance group or something, then they should be burned alive without inquiry.
Totally made of win.
Oh, I see, you’re advocating a “don’t ask, don’t tell” policy? Intolerant bastard.
Aw, you didn’t even get to use that real zinger about “People Eating Tasty Animals.” 
Some groups are open forums for discussion and debate.
Some groups exist to provide support and community.
Neither of these is a bad approach.
I guess I don’t see why there should even be antagonism about which one a group decides they want to be. If you want a debate, go find your self a debate forum. They’re not that hard to find.
I agree with everything everyone wrote here. I guess people often forget that the SDMB is a closed forum too, but the criteria is a little different: “You must be an anti-social asshole.” It’s in the fine print.
But your posting privileges only last for twenty minutes (and you must post deep thoughts).
I think he was straying in from his Anti-Choice thread in order to take up a discussion about animal v. fetus rights. Maybe to troll, maybe to learn and explore ideas – both are equally possible.
And yes I am self centered enough to believe it was my postthat had such a profound impact. 
Nah. It was over when I went all Dr. Seuss on his ass.
Wow, a group of like minded people want to be left alone to socialize. I imagine it’s a new concept that they don’t have to let you in if they don’t like you or want to. Other than to antagonize the group about why they should eat meat, what purpose is there to posting there.