I get the feeling that nowadays it's more about not getting shut down or in trouble with law over actually protecting innocent eyes. In the long run it might help with ensuring only the right people have access to more mature content, but it often winds up being pedantic and even absurdly obstructive to legitimate observers. Mosaic censorship in porno vids on a site that doesn't even incorporate anything beyond a simple login process or a "hey, you 18 by chance" popup comes to mind.