Wikipedia

One explanation for vegaphobia is founded on the meat paradox: many people who eat meat do not like harming animals. Vegans remind them of this cognitive dissonance, and one way to resolve this inner conflict and reduce dissonance is to maintain prejudice against vegans.

I find it quite interesting how often meat eaters in the west will be prejudiced against people who eat dogs - as if there's any other difference than the cognitive dissonance of seeing one as a pet deserving of a dignified life and the other as a tasty steak to chow down on.

My intuition is that this is mostly projected insecurity. For somebody who's doing something ethically questionable, it's pretty handy to have some group on hand to blame for being self-righteous and insufferable and so on. Very convenient indeed.

PS: ethically questionable does not necessarily mean "bad" or "wrong", but it is undeniable that vegans and vegetarians cause less animal suffering and environmental damage than the rest of us. Anyone who can take a deep breath and look at things rationally should be able to admit that.

What's not mentioned is going to a group lunch or dinner with someone who has a very restrictive diet and can basically only eat at one place.

Not excluded, not belittled, but you hear a collective sigh/moan when that person joins.

I will just mention “Troll 2” as the epitome of Vegaphobian movie.

If you are curious I also suggest you to watch “Best Worst Movie” (2009).