Navy Federal is a restricted banking system and only people from the US Armed forces, current or veteran, or only their families can have an account with them. It is not a public service like Visa and Mastercard, so it does not have the same regulations as them.
While looking it up, yes they do restrict nsfw purchases and a lot of other things, and from the looks of it, it is much worse than Visa and Mastercard. The thing is though, this is something that looks like it has been around for awhile and is likely in the agreements you have to sign to even have an account with them. With Visa and Mastercard, this is something new and not in their agreements at all.