why do vegetarians have such a bad reputation?!

For the same reason that some people hate gays, jews, blacks, muslims etc. They are small minded and incapable of understanding the fact that humans are a diverse mob and if everybody always agreed we'd never have evolved to the point we did, since problem solving under the influence of specific environmental conditions demanding high levels of social cohesion is what led to the development of our big brains.

If you extract vegetarians into the subgroups of activists vs non-activists then it is easier to see why this minority group has been chosen by the low brow among us as targets for vitriol. Activists have been fighting for social change for the last 5 decades and are always looked down upon by members in society- feminists, environmentalists, human rights activists etc have been or are still depicted by certain stereotypes. Animal rights activists are the newest of the bunch, and since many of the other types of activists are also vego (since vegetarianism is integral to effective social change) then this is where the mistake comes from. But most vegetarians are not activists, and as you can see by the answers from non-veg members activists are resented for daring to have a voice and an opinion which differs from that of the average non-thinking consumer. I'm sure abolitionists and suffragettes were regarded in similar ways back in the day.

vegan biologist

Not vegetarians in general but those few vegetarians who think they are better than everyone else and like to lecture people. These are the ones who speak the loudest and the natural thing is to associate ALL vegetarians with these fanatics.
Why do most people think all Muslims are fundamentalists and suicide bombers?
Stereotyping has basis in fact.

I think that in general most vegans are perfectly nice people it's just some people on this site that act as if they are superior to meat eaters and try to push their diets on other people. These are the ones that give vegananism as a whole a bad reputation.

Some vegetarians can be very arrogant and judgmental towards people who don't share their lifestyle. It's the few annoying ones that make them all look bad. People also just like trolling anyone who's different.

Probably because the stereotype vegetarian shoves their ideas of being a vegetarian down other peoples throats. It's not true, but it's the stigma attached to it :/

Same reason anyone is judged some irritating person that is part of a group irritates outsiders then they think everyone of the other group is just like that person.

Our very existence shames the meat-eaters and they retaliate by spreading lies and mis-information about us

They ruffle the feelings of meat eaters.
And then hugs are needed.

Harm? They misrepresent the dangers of the veg*n diet. Read this site and you'll find them assuring potential veg*ns that they don't need B12. (They do and it's not available in plant foods.) You'll see them claiming that veg*ns live longer. (They don't.) You'll see them claiming meat is full of worms, unhealthy, polluted. (It isn't. In fact, there are many more food recalls on fresh veggies than on meat.) You'll see them claim animals are tortured when they're killed. (They're not.) You'll see them claiming they gave up meat so no animals would die. (Their diet kills animals, too.) That's why veg*ns have such a bad reputation.

Its the ones that look down from their pedestals and condemn people for eating meat. And the ones that call people that eat meat murderers. These are the vegetarians that give others a bad name.