The issue is treating all third party stores as side loading, when no other category of device does this. It violates EU anti trust laws, and possibly US antitrust laws as this lawsuit explores. We trust people to have figured this out for PCs and macs, mobile is quite literally no different at this point.
Neither are good options, as the only correct move for the US is to withdraw from the region and accept whatever refugees come out of it as recompense for enabling this conflict.