Why do christians say "hate the sin not the sinner" when they just shouldn't preach hate at all?

I just don't understand preaching hatred at all. Besides when it comes to fundamentalist why do they care so much about other peoples business anyways. Like i went to church and bible camp and bible study until i was fifteen and all the time we were told to push are faith on to others and not have partners or friends who were not christian. I still study Christianity and it still seems to be the same way, you want everyone to be christian. Im agnostic and i don't push my beliefs on others, I'm a lesbian but i don't push that on anyone. I think people are who they are and you cant change that. I made an informed decision about my beliefs but i guess I'm still going to hell because I dont think I'm doing anything wrong and I won't apologize or repent for that. I just don't understand because i think everyone has the right to believe what ever they believe to be true but you shouldn't push it on anyone. Why in the eyes of the lord am I an abomination? Please don't just say god loves us all because I know a lot about christianity and god seems to be about punishment more then love. otherwise there would be no hell. I just think any form of hatred is wrong and you shouldn't preach it. I don't think all christians are bad or anything, mostly just fundamentalist christians kind of scare me....