How dare you bring an argument with logic and statistic in a discussion about lgbt!
But yeah, interesting idea. How many of the top listers are tagged in a way that you can find them easily. Or rather, distinguish them from stuff that would not interest you.
Though optional content or possibilities are an interesting subject. There are games where the mc and interactions are freely choseable. This is more like a life simulator. Does this even qualify as "gay", just because you could play it that way. Even play it exclusivly that way. Would you search for something like that with a gay or with a straight tag? Well, I would not tag it gay, as it's focus is not. It's focus would be simulation and lewdness and customizablity. But this is my opinion, since there are no user tags, we are at the mercy of the dev, what tags are given.
As long as we do not have user suggested tags, tag filtering is rather moot anyways. You need to rely on tagging by the dev. And let's face it. They will have a different opinion about the tags of their game, than the players. I liked that example about the different lgbt tags. Will you find yuri, if you search for lesbian, but the dev did not tag gratiously? Is yuri even lesbian or is it specifically lesbian in a romantic way that may or may not be sexual and should have anime style graphics.... ;-)