I'm not saying that the age of an account (strongly) argues against the account being Newsome's, I'm saying it (significantly) increases the disutility of wrongful banning. Which in turn argues for requiring a higher level of certainty for banning an older account. Hence, the distinction between "plausible" and "conclusive" becomes relevant, where it wouldn't be so for a new account that only had a few very-bad-and-highly-suspicious comments.