I think you're miss understand.

From where do you know they're offering an "Anonymous feature" ? Stake never offering you an anonymous feature since the beginning of their release. You also can check with and verified with WaybackMachine: https://web.archive.org/web/20181214053452/https://stake.com/terms-of-service

They never offering "Anonymous feature" and their term & condition is always have some right to ask you some "KYC".