Anyway, I'm an onlooker and have no affiliation with ttrpg.network - I just like sticking my nose in places where it doesn't belong.
I agree that the ban on NSFW content should be disclaimed in the sidebar, but at the same time, I think that's the community moderator's choice. IIRC DNDMemes on Reddit also blocked NSFW stuff.
However, I'd like to point out that ttrpg.network has open community creation and an explicit NSFW allowed stance. You could easily just create /c/spicydndmemes or something and designate it as where to put all your snitty pics. Although there are moderation concerns and potential drama with NSFW communities which have to be considered.
I'm all for having NSFW friendly places, but at the same time, if people want two separate communities for NSFW and SFW stuff, that makes sense to me. Nothing stopping people from subscribing to both of them.