These are great examples of the silliness of a left/right model of the political spectrum. While the Islamists hate America and our freedoms as much as our homegrown lefties they hate us for different reasons and in different ways. But in no way can an Islamist be called "left".
And gangs? C'mon. Those are the most apolitical people in the country. I imagine if you were to plot their stances on things they would be all over the map: Anti-tax, anti-regulation, pro death penalty (obviously, they inflict it regularly), anti-family, anti-war on drugs, pro crime, etc. Very tough to place them in a camp.
Some smelly French idiot 200 years ago noted that birds of a feather sit together and now everyone is locked into a less than worthless linear, one dimensional mental construct. I find the horseshoe model (introduce by another Frenchman) much more accurate and when you then apply the "who is more violent" concept you find that those who wish to impose their views on others contains almost all of the political violence.
Libertarians seldom go around killing people to make a point about now much they want to be left alone - except in self defense or when being raided. Even the horseshoe model would have trouble placing them on the spectrum.
If the horseshoe model used "individual freedom" at the top and "coercive government and/or coercive means such as rioting and killing" along the two legs of the horseshoe then it would be more useful.
And you would see that all of the killings come from people who think those who disagree with them should be dead. Tyler Robinson and Timothy McVeigh are very very close to each other although both would be aghast to hear that.
https://en.wikipedia.org/wiki/Horseshoe_theory