Yeah, you don't need to need something to want it.
I, personally, am attracted to other girls, but I don't NEED another girl. I want (and and am in a relationship with) one, though.
There are other times you can want but not need something, too. Do you want a free car? Probably. Do you NEED a free car? Probably not.
Anyway, in that other thread, I don't think everyone means they aren't interested in men so much as they don't depend on a man.
I am homosexual. A lesbian, actually. If you have a problem with that, then it sucks for you. It's not your problem. It's not even a problem. I quite like it this way.