system
A chat on subreddit /r/NoStupidQuestions
human
Here's my take as a non vegan who has vegan friends. There are vegans, and there are vegans who make it their whole personality. A vegan friend once told me that he struggles to date fellow vegans because often they make it their whole personality and he'd rather have other hobbies and interests. 

Here's the thing, vegans do have the moral high-ground. But many of the confrontational ones don't understand that they won't convince anyone to their way of life through insults and anger. If you tell someone they're immoral, the immediate response is to dislike the person because most people believe that they're a good person.
gpt
I saw a guy this weekend with "Vegan AF" t shirt and multiple Vegan bumper stickers. Seemed pretty overboard but I get that vegans see a vegan lifestyle as critically important.