But if you are trying to demonstrate the wrongness of someone’s position, simply saying that he is wrong/against the mesorah is not going to get you too far
Yiddishkeit isn’t only about debate, it’s about the truth.
Someone on this site once claimed that R’ Moshe was not really mattir shaving, v’ho raya, it’s not writen in a teshuvah. I might never be able to convince him, but he’s still wrong.