Pseudonymity beats anonymity. People's track records and comment history should be a factor when judging what someone says, unless we expect every comment to be a lengthy thesis.
If I see a comment from someone I know to be a relative expert on a field based on my previous interactions with them, I want to judge it as more authoritative and interesting than a rando who registered two weeks ago and has mostly commented "lol".
Also if you use old reddit usernames in reddit are as impersonal as they are here because of no discernible avatars.