1) If you think that's where "homophobia" came from, you are mistaken. The root of that "homophile" is akin to the Gay Movement of the 50's, homophile was the name of the movement. "Homophobia" came from those men that were straight that had a fear they were perceived as gay. It isn't a fear of BEING gay or a fear of gay people, but rather a fear of being perceived as gay. Or you can use the psychologist's own definition of the word since he made it.
[A] phobia about homosexuals....It was a fear of homosexuals which seemed to be associated with a fear of contagion, a fear of reducing the things one fought for — home and family. It was a religious fear and it had led to great brutality as fear always does.
Was it effective and useful a change? Well it wasn't a change. The phrase "homophobia" or "homophobic" wasn't even defined until the late 60's, early 70's, so technically it has never changed.
2) And what differences are being promoted exactly at a gay pride or parade event? And why are they irrelevant? The purpose of the parades is to show people that sexual orientation SHOULD be irrelevant in society. It is to give visibility to onlookers that lots of people are different in lots of ways and that we should still all be equal, even if we are all so different with walks of life, etc. That's why I support a straight parade or white parade if there is no hate speech and all of the messages are positive, like they are in a gay parade event. There is never any talk about "breeders" and no one is excluded from a gay pride event. Quite honestly there are the PFLAG and Gay-Straight Alliance organizations marching in the parade to promote equality and unity between people of different walks of life.