OK, throwing myself to the lions here, I confess that I say things are "gay." I said it
constantly as a teen. Things were gay, people were gay, clothes, situations, ideas, etc. Some things were just "gay" while others were "totally gay." It still slips out of my mouth sometimes, even though I do try to speak like an adult IRL.
However, it has no more to do with the meaning of "gay" as in "homosexual" than gay/"homosexual" has to do with the meaning gay/"happy, lively." All three uses are totally different.
It is in no way intended as an insult to gay people. Like I said, it has an entirely different meaning. And one all its own.
So, there you go.