In giving a rundown of what I found out there on the matter, I wanted to reference the existence of some conspiracy theory type speculation, since it is out there, but without harping or promoting any of it.
But, since you asked . . .
There is speculation that other orgs might want to dissuade the Mets from blowing up the market for Yamamoto and other high profile FAs. There is speculation that some orgs want MLB to crack down on a group of the most egregious misusers of the IL. There are even further out theories as might be expected.