[krisoft]

> Most statutes here in the US do, just for clarity.

Not a lawyer, so i can’t say if you are right or not but there is a very famous US Supreme Court ruling which basically said “I know it when I see it” about obscenity. That suggest to me that perhaps the definition is not as clear cut in all cases as one would imagine (or were not as clear cut back in 1964).

Quiting from https://en.m.wikipedia.org/wiki/I_know_it_when_I_see_it

The phrase was used in 1964 by United States Supreme Court Justice Potter Stewart to describe his threshold test for obscenity in Jacobellis v. Ohio. In explaining why the material at issue in the case was not obscene under the Roth test, and therefore was protected speech that could not be censored, Stewart wrote:

I shall not today attempt further to define the kinds of material I understand to be embraced within that shorthand description ["hard-core pornography"], and perhaps I could never succeed in intelligibly doing so. But I know it when I see it, and the motion picture involved in this case is not that.