It is to me absolutely clear to me that Amazon is benefiting from the work MongoDB has done, and without commensurate compensation. (Is anyone proposing Amazon does not benefit?) And having watched Microsoft embrace, extend and extinguish way too successfully, it is at least a concern that the effect of Amazon's action will be to the long term detriment of MongoDB.
This to me is the problem that must be solved. One possibility is to modify the OSS model and licenses by creating a distinction between the members of the community and non-members like Amazon and Apple. If you want to use any OSS software (with the new license) then you must become a contibuting member of the community. If you don't want to be a member, then NO OSS software is available to you. In other words, Amazon could not pick and choose which OSS to use, but only to be a member of the community with all the benefits or not.
I'm not saying this is the answer, but I am saying this is the problem we need to solve.
OSS is an ecosystem - one that should and must protect itself from predators.