It's not about what's against the ToS, it's about getting the monkeys who review the reports to judge that it's against the ToS. Given their working conditions, they have little incentive in making an accurate determination and may just be pressing buttons at random, so spamming enough reports will eventually yield a ToS violation even on perfectly clean content.
Your question contains the implicit assumption that "TOS" is some bright shining line that everyone, from all posters, to all of the AIs and humans analyzing whether something conforms, completely agrees with. Therefore, "just don't break the TOS" is a reasonable solution.
This is manifestly and obviously false, in numerous ways. I don't even need to cite capriciousness, cultural differences, or potential political bias; even ignoring those things, it simply isn't and can not ever be a bright shining line.
This is even before we consider that TOSs have been known to retroactively change. YouTube just made such a change; doesn't affect whether the videos are removed but the retroactively changed the monetization standards, with large effect. "Just don't break the TOS" is a non-starter in such an environment.