Note how they progress on the slipper slope from extremist content to violent extremist content. Anarcho Capitalists, Amish, Alt-Right could all be labeled extremists. But they are not violent.
Palestinian Terrorists are supported by a majority of UN delegates. So, by definition they are not extremists.
A big mistake is made by not clarifying the difference between those two types of people and groups of people.
Yes, there is overlap between the two groups. But there is also overlap between male and each of those groups, and between many other factors.
I guess this is why Steve Bannon wants them regulated as a public utility.