What does it matter where physically computers are located? If the owners can be imprisoned in US, the will cooperate with US government.

Surely if this were the reason, you'd just put it in international waters?

You can't launch from the US without the federal government giving you permission. And SpaceX does not have (nor are they planning) any launch pads outside the US. [And because of ITAR, I'm not even sure they'd be allowed to build one.]

However, I do think avoiding local control (state/city permits) is a reason for this.