Surely you mean this the other way around?
Mitchell is trying to address a social problem with a technical solution.
The problem is technical: too many low-quality PRs hitting an endpoint. Vouch's solution is social: maintain trust graphs of humans.
But the PRs are increasingly from autonomous agents. Agents don't have reputations. They don't care about denounce lists. They make new accounts.
We solved unwanted automated input for email with technical tools (spam filters, DKIM, rate limiting), not by maintaining curated lists of Trusted Emailers. That's the correct solution category. Vouch is a social answer to a traffic-filtering problem.
This may solve a real problem today, but it's being built as permanent infrastructure, and permanent social gatekeeping outlasts the conditions that justified it.