Unfortunately it's a fact that being gay means being in a minority and all minorities have, historically, been marginalised and persecuted to a greater or lesser extent and still continue to be today - either overtly or covertly. It's a social phenomenon that crosses all cultures and creeds. Being too fat, being too thin, considered to be too ugly, having wonky teeth, being disabled in some way, being of a minority race within a dominant racial group or even having ginger hair. All these things mark people out as being different, simply because they are in the minority.
Education and social conditioning is the only thing that will stamp out picking on minority groups but, unfortunately, years worth of telling people that it is wrong, trying to educate, re-educate and inform them and even passing legislation to make it a criminal offence to perpetrate discrimination/abuse and causing offence to some minority groups seems not to have made that much difference.
I'm not saying that people should stop trying, just that it seems to be a constant battle for many minority groups. It's quite right that they should not have to put up with it, or be prepared to put up with it.
For what it's worth, I think that over the last 30 years or so, huge leaps have been made in homosexuality being accepted and "normalised" in a society where it was hitherto seen as unacceptable and abnormal. Many gay people are now totally mainstream in the entertainment world and in the media. Most people know people in their work or social circles who are "out" and it's no big deal at all. As I said in my previous post, people will always counter that argument with anecdotes about people they know who have suffered homophobic abuse but I truly believe that most teenagers nowadays do not have the same view of homosexuality that they might have done 30 or even 20 years ago.
In fact, I'd go as far as to say that as minority groups go, gay people have made far greater strides in gaining societal acceptance than many other minority groups have over recent years.