I feel like part of the problem is that your position is changing based on outcome, right, like it became a problem after the fact when it became a commercial hit.
Not even for biology/medical textbooks or forensics training content or other educational purposes from commercial publishers?
I don’t see naked as equaling sexualized and I don’t see the Nirvana cover as the latter either, but I definitely can’t see a total ban on pictures in commercially-sold material being workable.
If your position is something along the lines of, babies cant consent, young children cant consent, why dont we just live in a world where we dont include them in media so we dont have people growing up having to figure out how they feel about how they were presented to the world... sure, that would be a pretty consistent world view.
If its just that you think a naked baby is pornographic then I guess its an entirely different conversation. Its not really clear what motivates your statement here though.