But this story is about state-criminal relations - people like these are terrorists, and we have laws against terrorism, so it's just the matter of enforcing those laws.

If you mean, when one should start worrying about one's political opponents, the answer is, and always has been - as soon as their support starts growing for any reason. In that sense, the time for anybody on the left to worry about right-wing extremist politics has been many years ago, as was the time to translate it into action (i.e. vote strategically to defeat them as the highest priority).

That's true, but it's often not so clear-cut, nor does it line up with electoral goals or established political parties in many contexts.