I wish we could implement a “I know it when I see it” policy to ban pornography but I am such a degenerate I know for a fact that degenerates like to hide their fetish in plain sight, anyone who is familiar with concept of a “dogwhistle” knows what I’m talking about.There is no good way to distinguish what is and is not pornography.
All you can(and ought to) do is establish a practical standard and enforce it.>you can show X but not Y>You can show Z when X but not Z without X>You can post X here but not X and Z. That goes over there.And just accept that this won't create your utopian world free of pornography or the harms of pornography, but just that you can confine it to adults making their own choices.