Irrelevant of the moral issues that this poses, such content is illegal in many countries (e.g the UK). Continuing to federate with lemmynsfw.com will put users at risk of significant legal repercussions.
Please would the admins consider defederating unless lemmynsfw change their policy.
UPDATE: The lemmynsfw admins posted an clarification here: https://lemmynsfw.com/post/29826. My original argument for defederating doesn't stand any more.
Child sexual exploitation refers to the sexual abuse of a person below the age of 18, as well as to the production of images of such abuse and the sharing of those images online.
says the same applies to drawings and AI generated images.
That's up to the interpretation if individual country courts, but I would be wary nonetheless about pictures showing people that could look like teens.
Edit: downvote all you want, laws are laws, if you like to risk it, good for you, I don't.