Categorically no. The point of lemmy isn't to be a content farm. It's to be a community where people respect each other. How can you respect anything or anyone while stealing content?
In fact I would go the other way and start banning people that are posting content they don't explicitly have permission to post. In this day and age where more people are seeking to monetize sharing nudes, we need to protect the few free content creators we have left, whether on this platform or the former one.
Fuck people and bots that steal nudes.
I would argue that we're no more entitled to post people's hentai artwork as we are their nudes. More so in fact, it can take days to create hentai, only for it to be posted here with no mechanism for the original author to request it taken down.
If people really want to see other people's hentai posted here, why not link to it? I'm pretty sure the original authors would appreciate that. Plus if they see Lemmy generating traffic, maybe they'll join up and post stuff here directly.