While you hit on a genuine problem, there are far fewer legal barriers to Google, Facebook, Twitter or Microsoft terminating your account than for US ICE to seize your .com and .org; ICE needs a warrant for seizure and more to retain indefinitely. Further, you can always get a non U.S. domain, e.g. .ch (Swiss) as used by Wikileaks.
That's unless you live in a country where it's becoming commonplace to filter out DNS. I'm honestly hesitant to have my online identity be obliterated at a whim by some reckless government of mine (France); they won't seize my dotsomething, but they will legally be able to block it out of existence, nationwide, without even the order from a judge. In that case, there are actually more legal barriers to Google terminating my gmail account on my government behalf than being blacklisted.
