Not everyone acts rationally even when knowing that they act irrationally.
Yet they kind of did. I've limited participation in my libraries with GitHub's setting that nobody who made an account in the last 6 months can do anything in my repos (after some misguided hustler thought they're an easy target and posted an ad).lp
Time's marching forward though. Wonder what will happen after a few more months. We'll have bot spam accounts that are no longer as fresh.