The word "extremist" with no further qualifiers is pretty useless, as it is a description of something relative to the average and thus something can change from being non-extreme (normal) to being distant from a new normal only because everything else moved but that being described remained still… or vice versa.
It was e.g. for a very long time extreme positions to be for abolition of slavery/for parliamentarism/for women's equal right to vote/for equal LGBT-rights, etc,
but then the average/normal opinion of society changed to being neutral and then to those remaining at the previous normal positions now being the only extreme position remaining, as the previous "extreme" positions are overwhelmingly considered the only socially accepted ones.
So generalizations like "all extremism" is probably not what users intend to describe.
Just saying… consider being more specific.
@bigduke Mhmm. Those people then also tend to be absolutely unable to comprehend that their own extraordinary level of intolerance and repression against people deviating from the current ruling norms can be described as and is another form of extremism, usually "centrist extremism",
as the ranges that people's opinions and actions are describable on isn't limited only to the ones they tend to over-simplify it to ("left/right" or "religious").
...should also be mentioned that it's not just those having "extremism" thrown at them as a method of delegitimizing opinions divergent from the current ruling norms that may described as such, but also often those doing that themselves, due to their extraordinary level of intolerance and repression against deviation from those norms can be described as and is another form of extremism, usually "centrist extremism", even though they tend to be unable to comprehend that the ranges that people's opinions and actions are describable on aren't limited only to those they tend to over-simplify it to.
Like when a State's "national coordinator for safeguarding democracy against violence-endorsing extremism" declared an autonomous-leftist group such "extremists" while their most "violent" act was shouting a bit against Capitalism with a banner at an apartment store, then leaving.