I think the reasoning is that understaffing means each examiner can't spend as much time looking for prior art, so things might be patented that should have been rejected by a lengthier prior art search.

The USPTO would still have an obligation to process the patent applications though. So now each patent has an average of 4h20m spent on it instead of 4h40m (some are hundreds of pages of complex concepts that potentially no one in the world has seen published before).

The examiner then would be under pressure to glance over a lot of applications and just let the courts sort it out later.