If the PR does what it says it does, why does it actually matter if it took 2 weeks or 2 minutes to put together, given that it's the equivalent level of quality on review?
For some people, the point was precisely to improve the software available to the global commons through a thriving and active open source effort. "Too many people are giving me too many high-quality PRs to review" is hardly something to complain about, even if you have to just pick them randomly to fit them in the time you have without AI (or other committers) to help review.
If your idea of open source is just to share the code you wanted to work on and ignore contributions, you can do that too. SQLite does that, after all.
You're right that the issue isn't how many minutes it took. The issue is that it's slop. Reviewing thousands of lines of crappy code is unpleasant whether they were autogenerated or painstakingly handcrafted. (Of course, few humans have the patience and resistance to learning to generate the amount of terrible code that AIs do routinely).