I agree, but that said, you - or a shows writer - can't be afraid to make a villian gay. Because then you're going to far towards political correctness.
One of my favorite sci-fi novel is "Dune," the chief villian, Baron Valdamir Harkonnan, is a homosexual (also a pedophile and a sadist) having him be such in no way harms those of my sexual orientation.
I don't find gay psych or evil charactors insulting in the least. We are the good people and the bad.
So maybe I don't agree
Oh, no, not at all. I love the Dune series, too. Herbert, and his son in carrying on the series in later books and prequels, created a thoroughly loathsome villain in the Baron. They didn't use his being a homosexual as shorthand for "evil" or "twisted". It was an incidental detail about the character that wasn't given primary focus or play.
I don't automatically find making a villain gay or bisexual offensive. I find it offensive if that's the primary way the writers try to use to drive that point home, and there are way too many examples out there where they do just that.