Why are vegans vandalising signs?

It is a religion and they are fanatics.

Because they are fanatics by the definition of the word. They're not content to just be vegan themselves, they want to force their ideology and life choices on everyone else. Yeah guess what, that tactic is not going to win any people over, but it will just make people hate vegans more (even if the majority of them aren't like that).

Well at least the artist didn't push someone onto a railway track.

That best answer is harassment (and wrong)

therefore I'm reporting it and your question

You anti vegans are far worse than the vegans you demonize

are you sure you didnt do this?

Why are you associating the vandals with what they eat..? It likely has very little to do with their willingness to draw on stuff. Don't you remember being 17..?

Some - not all, or even most, - are very militant, and want to force others into their ways. Although there has been an increase in the number of vegans, and vegetarians in recent months, they are still a vocal minority, and the vast majority of people eat at least some meat and/or fish and the majority of those who don't are lactovegetarians.