Arguments are best when they don’t engage either member’s identities. For this reason, Paul Graham says to keep your identity small. The title summarizes it well, but the why is important.
If you are interested in the truth, then be prepared to follow arguments where they lead instead of letting the identity of the author interfere with your reasoning.
For example, suppose two scientists are publicly debating the precise value of climate sensitivity, but one of the scientists is from Berkeley, where you also went.