Yeah, this is a well-known controversial aspect of PNAS publishing. However, not all uses of this track of publication is necessarily nefarious. See this for instance --
https://www.nature.com/news/scientific-publishing-the-inside... . I was also told that use of this track is some times for very mundane reasons too --- like a professor trying to help a struggling grad student satisfy PhD requirements such as needing X number of papers to graduate. More often than not, good ideas do get held up in other journals for all kinds of non-scientific reasons. I've certainly not seen too many examples of overly-erroneous science in this track either, at least in genomics.
I do thoroughly understand your concerns and distaste here that this allows prominent academics to push their (possibly incorrect) views/results on something far outside their expertise. I would love if PNAS publishes the peer reviews for papers such as these that pertain to ongoing health crises (eLife makes peer reviews public, but keeps the reviewers' identity anonymous).