As someone who lived behind the iron curtain, you may not realize this, but people lie.

Something or someone calling itself leftist does not mean it is. The USSR pretending to have been socialist is about as authentic as the Democratic People's Republic of Korea being a democracy.

Earth Liberation Front is about the most violent actual leftists example you listed, and even they pale in comparison to what the right wing does, and is again an appropriate response mechanism for permanently altering the climate of the entire planet in a devastating way for the fictional concept of money we have collectively decided to value. If anything, again proving my point of too little too late when you consider the consequences, and considering they formed back when there was acid rain literally happenings due to pollution.

The right is inherently violent because it's an ideology of power and authority, not union and equality. Belief in power and authority is inherently violent, because subjection of humans goes against the inherent will of personhood, and will inevitably lead to conflict. The pursuit of power is also inherently violent, because it requires therefore forceful subjection. That's why all authoritarian governments are right wing.

I can think of only one example in recent human history that broke that mold - only one dictator that, as far as I know, sought power solely for the purpose of improving their country and the lives of people while eliminating corruption, that being Lee Kwan Yu. They were the closet I've seen to an actual violent leftist ideology, and their governmental system remains an outlier in that it's a democratic competitive authoritarian system.