>>508891319
Real answer, first it comes from Roth v. United States.That created the Roth test.
>Justice William J. Brennan Jr. created a test to determine what constituted obscene material: Whether the average person, applying contemporary community standards would find that the material appeals to a prurient interest in sex, and whether the material was utterly without redeeming social value
Then it got changed in Miller v. California to include
>serious literary, artistic, political, or scientific value"
This is why Muh art comes in
Next we come to cae Jacobellis v. Ohio and The state of Ohio said the movie was Porn. The film sued saying it was art, and they were opressing the artistic intent. The supreme court ruled it wasn't porn after watching it. This resulted in the know it when I see it standard
>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.
~Potter Stewart
since then no one has really cared.