I think that's an overreaction, to be honest. The names you mentioned are very much used by real royals, and I didn't see Anneza's comment as offensive - different people will think of different names as regal. And I don't think someone expressing that they don't think a certain name is regal is gatekeeping.
masculine list:
https://www.behindthename.com/pnl/191050/124079feminine list:
https://www.behindthename.com/pnl/191050/124080