They operate where this is possible; if, for example, Signal operates in North Korea it is not because they have offices there, but because some people in NK ca

They operate where this is possible; if, for example, Signal operates in North Korea it is not because they have offices there, but because some people in NK can get a client and connect. If Signal would have offices in NK, it is guaranteed they will get to jail, not passing Go and not collecting 200, so Signal is not really operating in the countries you mentioned but users can utilize Signal there. In UK if Signal has any offices or employees, the UK government can force Signal to either put a backdoor in the product or move out of the country. The second choice is what Signal said it will do, it makes perfect sense - leave instead of bend over.