Just curious, is there a way governments could somehow block access to those satellites or force the companies behind them to deny access for people of their country?
See above - two-way satellite equipment is illegal in belarus. There will be no legal way to buy an access point, and owning it risks you jail time. So most people wont have one.
Maybe some lone dude in the remote are can smuggle it in and keep it hidden, but if we are talking about mass movements, that terminal won't be mich use
Not sure, but I think the idea of SpaceX intervening with political protests in a foreign country is a little naive.
The controversy they would stir up, is likely not worth the risk for the company's public image. Also I don't think the technology isn even released yet...
There are national laws and international treaties that regulate usage of the radio spectrum. Without international cooperation, many radio applications would be impossible.
Article 18 of the ITU Radio Regulations was mentioned in the comments on another post. It basically states that nobody can use radio in any country without permission from that country.