Noticed that with another game and according to a person on here it was because the game used ai stuff in a way that violated dlsites policies no idea if that happened here.
Let's clear up some confusion real quick. It's the credit card companies. I'm not sure which ones, but they've been threatening to pull out their services if DLsite keeps offering 'certain' content to the west. And they did pull out, so DLsite tried to adapt. They renamed a bunch of tags. Now you need a Japanese IP to view games containing certain tags. Loli is the obvious one, but there's some stranger ones in the mix like some uniform tags. Seems like they've managed to get their services back with the compromise.
Apparently, games with AI art are also restricted by country, but the distinction is important to make considering how... quickly people will resort to harassment whenever they have a whiff of AI involvement. If one desires to get past the IP restrictions on tags, you pretty much need to resort to a VPN at this point. A lot of developers are apparently responding by removing offending tags from the listing (without removing the content from the game), so this drama will continue to evolve for some time to come.