Not in principle. Practically all democratic systems have provisions to defend against subversion of their core principles. Those provisions may be designed to

Not in principle. Practically all democratic systems have provisions to defend against subversion of their core principles. Those provisions may be designed to safeguard institutions, processes such as elections and regulate information flow. It's important to remember that the US concept of "free speech" as an absolute right is very untypical, and that it also has limits due to being narrow in its scope. Of course, banning a social network due to arbitrary or without reasons would be against democratic principles. But following democratic and legal principles to openly apply laws and procedures designed to safeguard the state - that's not undermining at all, to the contrary!