Comments made by recent accounts appear with green names until a grace period passes.

HN prefers "legit accounts" (subjective) - good faith comments from real people, reasonable uses of alias and spun up fresh accounts for regulars to say things without being part of their main history, etc. New commenters welcome.

There are obvious and less obvious dark patterns of bad faith account creation.

The admins do a pretty decent job, sweeping cobwebs without hitting real genuine people is an artform ...

Returning to the main GP point - there's a lot of low key background churn activity that can result in "inexplicatable" votes, some from bots and some from the general case of "people are strange".