Yeah, basically, the tags are in the range of 0-3. It's really 1-3 but I'll explain that in a bit. Basically, if there is something that exist in the game, but just a small amount you go with 1. If it exist in a moderate amount, OR it's maybe a singular character, but is decent part of the story, you go with 2. If the game is oozing a certain tag, then it's a 3.
Now, how can it get lower than a one? Well, if there is disagreement about a tag. If I said there is NTR 3. Well, if you're a user, you can vote on the tags too. If you feel that the NTR 3 is too high, and it's more like NTR 1, you can express your opinion by using another option. -3. The -3 option says "Hey, this tag doesn't even exist in this game" and it's designed to go against trolls or people who are mistaken about tags. So if someone puts the NTR tag, someone could counter it with a -3 and cut that persons influence in half. The more people people add to it, the more accurate it gets. Well, theoretically.
For example, I actually just updated the tags on VNDB on Among the Stars. I did NOT add NTR to the list of tags because it's not technically NTR. VNDB has a better tag (that I suggest on almost a daily basis SHOULD be on F95zone) called "
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". This tag better encapsulates the intention behind the the characters actions. She (Kate) didn't knowingly engage in sexual relations against the MC, just that she is involved in sexual relations with a person other than the MC because of reasons in the game. The difference is that on this site, there is no such tag, so we have to use NTR as the tag that's closest to cover all of that stuff up.
I hope that made sense. Have a good day!