Only it will also apply in reverse. Taking Rafster example here. A game with 99.99% gay content and 1 optional hetero sex scene will end up with both gay and vaginal (assuming it is vaginal sex the game has). So the 99.99% gay game won't be shown if you remove all games with vaginal.
That happens with my game. I admit, I have a kink for very specific sissification scenes or a very specific type of trans man porn (Very hairy, masculine, bearded FtM guys), so yeah, it got to my game. Do I needed? Nah, but it's one of my kinks and I wanted to be there, so, for transparency, bam, I got the sissification/trans-futa/vag sex tags. I could have hidden them, but it wouldn't be honest. I guess most of gay dudes here who search excluding vag sex/sissification would not see my game, even though those encounters are optional (well, the sissfication scenes can't be avoided on the storylines where they appear BUT even then, players can choose to not see the text and media related to it). Other games that have bisexual or some straight content, like Hornstown or Lust for adventure would also be skupped by excluding vag sex tag, and it would a shame because those game have a LOT of gay content.
So, it's good enough. You look through gay no vag first, and then, after it's done or you're bored, look through gay and vag for missed cases. I swear you're not even trying.
Anyways, for each game he misses, a hetero man misses a dozen by filtering out gay. So think positive.
There's not even need for that. Remember what MarshmallowCasserole said?
Unfortunately, you often can't define them neatly and easily. And specifically with gay content, you have it easy. You only need one peek at the game's page to know with certanty if the game's theme is gay sex. Really, just a glance at the thumbnail is enough in most cases:
That's how I find gay games here. I only filter by the gay tag, and directly skip the games with banners with women on it on the latest updates page. On the cases when the banner is completely neutral or don't have clues, I see the screenshots, and as a last resort if I don't see anything, check the thread because guys are VERY fast spotting gay games.
That's how I handle the gay tag here. I have to admit, for players who want lesbian focused games, this would be difficult because even with a banner full of women, this wouldn't work.