The only thing WotC restricts is their IP. That is, anything that they produced that's not in the SRD.
No setting is under any WotC SRD (notwithstanding FR and Ravenloft for DMsGuild).
So sites that posted all of the spells with spell descriptions, including the ones from PotA were asked to remove the offending content. Sites that include only the spells in the SRD, plus as many home-brew ones as they want are fine.
WotC has no interest or right to have you pull material from somebody else's IP. So if you make 5e stats for Dark Souls, LotR, Harry Potter, or anything that's not WotC, it's up to the owners of those IPs to determine what, if anything, they want to do. If your Dark Souls class used and published spells from PotA, then Wizards might contact you.
Note that policing IP is a very time consuming thing, so they have to find it, determine how infringing it is, and then pursue that.
The SRD is specifically so you can publish home-brew things anywhere you want. The only restriction from WotC is that you can't use any of the rest of their IP - that is, anything they published that isn't in the SRD.