@Revenant62 It felt kinda odd for him to use this specific phrase and I didn't remember that it's what Mizuhara told him before. What you said makes a lot os sense.
Unless your goal is to delete all comments, you can just stealthly edit the chapter content by uploading new set to the same chapter. That's at least what I did.
Next best solution you can do is blocking the group. Sure if they pick up some series for real you might miss out but I don't think that's a likely scenario.