Technically, the kinks are required to be in the current version of the game for it to get a tag on top. It's not really followed religiously because most games put incest, harem, and a bunch of thematic tags on there before we see it play out in the game.
What happened is probably some baby got butthurt over their precious harem tag being used for a game that didn't meet their personal requirements for a "harem game" and reported the tag. Since technically, it does goes against the rule of tags needing to be in the game already, it got removed by some mod. It wasn't removed due to Catherine banging the guard or anything like that.
Anyways, you just caved really easily. What's next? Make brothel whores exclusive to the MC? Make the King's concubines virgins? Make the King impotent? Lol... I know you didn't plan on doing NTR in the first place, but placating the dozen or so "harem" brigaders seems like a great way to limit your own creative process.