[nathanmcrae]

The paper addresses your first point in section 7 'Model Rationale'. Essentially, anything that is subject to self-propagation is going to tend to expansionism at a large enough scale, superintelligence or not. The only thing that would prevent this is wide-scale coordination (e.g. a universal autocratic government). And if any species did accomplish this, they would just be one of the 'quiet' ones.

That's my take, they wrote it better though. That section is short, straightforward, and worth reading.