How can people think that homosexuality is wrong?

I agree with you, people worry too much about one's sexual preference... or whatever they choose to be. That should be their own decision.

I think generally a few different factors lead into homophobic tendencies. Religion is one. Now this isn't to say  everyone who is religious is some crazed hate filled zealot, but someone people who condemn homosexuality refer to their religion and ideology as a basis to go off on what is right and wrong. 

Another factor could be environment as they might have been raised in a place or time where misconceptions and fear were key roles into homosexuality disdain .

I'm gay and my sister thinks it's wrong >.> I'm not sure why she feels that way, I'd support her no matter what. :/

I think homophobia is stupid, and unjust.  Everyone should be able to love who and how they want.

I have two bisexual friends, and I support everything they do, including decisions in their love life.

(big Malec shipper and Dumbledore lover here)

So sorry for the confusion and if I said anything offending I am sincerelysorry.  I feel really bad and embarrassed at the moment.  I think I got confused between homosexuality and homophobia, and that, obviously can change everything.