Pretty much some terfs and fascists in Australia pressured MasterCard and other payment companies to pressure Itchio to deindex the nsfw tag and there will be moves to ban some (or all) nsfw games to meet the family friendly values of these companies.
Viewing post in Lust Odyssey (NSFW Visual Novel) comments
Basically banks and payment company's are to lazy to make separate systems for different regions and are making everyone abide by the strictest standard, which is extremely dangerous. and the group is using the no mercy game from a few months back as a reason to remove every single nsfw/lgbt/bodily-health game across several platforms for child safety, and since these company's are lazy as hell they are going to not care if a site needs id verification, they just wont support them.