No one has ever called me a girl (perhaps because I'm masculine), but I would definitely be offended if someone called me a girl because I'm a boy.
It depends. I wouldn't mind if they're joking but I don't like stranger gay guys calling me babe. I don't even know you and I am certainly not your babe.
Never been called that. Is it a cultural thing - USA maybe???
Blah blah blah, something enigmatic sounding...