Nonsense. Besides the fact that the whole "agenda" thing is ridiculous, since when are all characters on TV supposed to represent only the "vast vast majority"? God forbid that anybody should have to see something on TV that doesn't reflect their own personal experience! Believe it or not, most of us straight people are not offended or bothered by seeing gay characters on TV. Nor do we think that TV exists only to serve as a mirror for ourselves. Hell, one of the great virtues of fiction (and science fiction) is to allow us to temporarily walk in someone else's shoes, be they straight, gay, or some permutation thereof.
Infinite diversity in infinite combinations, remember? Not "only the majority matters."
Plus, honestly, I don't know what world you live in, but modern TV does reflect the modern world. I'm not not going to play statistics games, but, personally, my friends, family, colleagues, and neighbors include both gay and straight people in plentiful quantities.. That's not an agenda: that's reality.
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