Sounds to me like you just hang around awful people, almost every single vegan I know loves beer and actually knows what they can and can't eat.
Sure, there is a tiny amount of fish stomach bile or whatever used in brewing (couple ml to the gallons) but that's usually only on nicer microbrews from what I've heard. I also don't care either.
You're mainly just referring to the fad diet vegan trend that's getting big, same with gluten free bullshit. Its just people wantin to do something thinking it will make them lose weight, but have no idea what or why they are eating.