The Supreme Court’s ruling only applied to obscene sexual material. It doesn’t apply to sex scenes within artistic works or sexual content in general.
There’s a test used to determine whether sexual material is considered pornographic. It’s known as the “I know it when I see it” test.
More info on this test here:
https://en.m.wikipedia.org/wiki/I_know_it_when_I_see_it
More specifically here is what is considered obscene:
The criteria were:
1. whether the average person, applying contemporary community standards, would find that the work, taken as a whole, appeals to the prurient interest;
2. whether the work depicts or describes, in an offensive way, sexual conduct or excretory functions, as specifically defined by applicable state law;
3. whether the work, taken as a whole, lacks serious literary, artistic, political, or scientific value.
The third criterion pertains to judgment made by "reasonable persons" of the United States as a whole, while the first pertains to that of members of the local community. Due to the larger scope of the third test, it is a more ambiguous criterion than the first two.