That's not easy. There will be tens of thousands of satellites. It would be prohibitively expensive to hit them all with missiles. Not to mention the debris cloud which, while temporary, would cause real problems for everyone in space for a few years.
More feasible attacks would be hacking the satellites or ground systems, RF jamming, or just locating users on the ground by their RF emissions and throwing them in the gulag. Or how about holding the Shanghai Tesla factory hostage? Less fancifully, China can put pressure on SpaceX via the ITU. There are plenty of options for China and there is zero chance SpaceX will try to break Chinese law.