The justification for a particular state does not come from its democratic nature. Plenty of democratically elected governments have done things which put them firmly in the illegitimate category. It is a fiction that democratic means free.
What makes a government legitimate is whether or not it actually respects fundamental rights. If you have a government that does so, there is no right to 'compete' with it, in the sense of carrying out one's own retaliatory force which is not subject to objective procedure. Such action presents a valid risk to the rights of the citizens of such a government, and it is justified in shutting down said operations.