Not OP, but it seems more reasonable to think they are choosing not to do business because they don't want to risk AWS deciding to shut them off and give them one day's notice to move their entire infrastructure.

Really, anyone using cloud providers should have at least a plan on a side burner to move to another provider if they have to. We've seen cloud accounts canceled for many reasons, including no discernable reason at at all.

absolutely agree. In this scenario though, it appears AWS and Parler were in communication for weeks prior to this according to the letter in the OP.

I see what you did there.