I'm already way accepting of long haired guys. I love them, nothing better than long hair on a guy. How does a guy look like a homeless person if he has long hair? I've never even thought about it that way. Of course taking care of hair is always good.
My boyfriend's hair goes down below his shoulderblades and it's really well looked after, so yeah, long hair on guys can be absolutely gorgeous. As long as he manages to find the balance between washing it too much and too soon, and he manages to brush all the tangles out of it, then it's great.
How long does it have to be to be considered long? All the women I work with have asked me to grow my hair long so I am, however, it is becoming a nuisance and its not long enough for a ponytail or anything yet lol