Edit: My comment took at face value the OP's claim that the Stellar account was generated without their knowledge. Obviously, if that claim is false, as Keybase

Edit: My comment took at face value the OP's claim that the Stellar account was generated without their knowledge. Obviously, if that claim is false, as Keybase's official response indicates, then my comment is invalid. Original comment: It does seem more than a bit questionable that the Stellar account is added automatically to the user's profile among a list where every other account/key/whatever in that list was manually added by the user. (As pointed out by the OP)