Just voted. But I wanna say with this rule translated from cartoons to real people, a user posting couldn't even post a picture of Sarah-Michelle Geller in the role of Buffy the Vampire slayer. The character Buffy is a underage teen, but the actor is like 23 or something. This is just a way to translate to the people who don't look at hentai who think like this.
So that in of itself is stupid. Remove the rule, have mods be more active in removing drawn stuff with like the mentality of "better safe than sorry" I would say.
And it seems people aren't reading what you are writing, Yay isn't saying lets allow pedos in here. He is saying lets use moderation more instead of banning a post with a picture of a milf version of Kim Possible.
Simply put.
Also you could have mods have a link to the rules above in all "boards" rule pages with rule34, cartoons and hentai. Maybe add an example like you have done with the links above but write something like "this and that is allowed, but this isn't" and maybe plainly write "loli isn't allowed" that will shoo most of the creeps away.
Maybe change Rule 2 to not include the aged up versions of drawings. That is simply what I am trying to say.