In theory Amazon could license the stack to a European Operator while having no operative access themselves.
I think this is already done in some cases altough the political reliability has not yet been tested.
If I run your software, you can have no operational control, but you can sneak a root kit or some kind of stuff I dont want to have there
I guess the question then becomes: what happens if some future US government pressures Amazon to revoke the license. Unless and until there's a good answer to that, it'd still be better to develop something locally.