I giggled at "scout mains." I don't have a problem with mini sentries, it's just a generally disliked tactic. It isn't a big issue to go soldier or demo and take care of them and grief the engi until he stops.
Yes, but you are a pyro main, and they can be impossible to kill since you have such a short range.
Play HL if you don't want nerds bitching at you for Minis.
Comp players still bitch about minis and dumb weapons.