That's not true... the term "terrorism" was originally used to describe the actions of states - it's only due to the media that, for rather obvious reasons, states have been "absolved" from the vastly greater levels of terrorism they commit in contrast to the comparatively minor levels committed by non-state actors.

So yes, this is terrorism. I't s not "eco-terrorism" (which is mostly a non-issue invented by the media) - it's bog-standard, common-or-garden-variety fascist terrorism. The kind the media goes out of it's way to never call terrorism.