okay... I think I understand that, and I definitely could see some of that.
I consider emotional make up and background (baggage?) as factors lead to the neediness. You said "They might cry not because they're needy but, because their just that way.". That is exactly what the guy might be afraid of.
Now it's different if this sort of thing happens once. Even once in a while--it's bound to happen at some point, right--after a fight or something? If I had a girlfriend right now, and she needed me, I'd be there in a heart beat. But if this was like...all the time, I would be out of there.
I guess the first time it happens, it might make a guy stop and think..."okay, is this going to happen all the time?" It would be scary.
It'd be a totally different situation if the girl is just a friend. I imagine that most guys can help a friend in need.