What is political extremism? The answer to that question is very simple. Political extremism is any ideology that those currently in power disapprove of.
In most cases the accusation of extremism will make use of the left-right political axis. The left-right political axis no longer serves any useful descriptive purpose but it is still extremely useful as a propaganda tool. Those whose views are out of favour can be labelled as extreme right or extreme left. These days the extreme right label is the preferred method of disqualification. Because that’s exactly what this labeling amounts to - disqualifying and demonising the views of dissenters. If someone is “far right” then there is no need to examine his arguments or to present evidence to argue against him. The fact that he has been declared “far right” means he is a wicked extremist whose views can be simply disregarded.
Mainstream conservatives tend to do the same thing - they think they can disqualify an opinion by painting it as hard left. Even alt-righters and their ilk will do this.
Of course left and right are now entirely meaningless political concepts but the idea of a political spectrum is very very attractive to those who have set themselves up as the gatekeepers of acceptable thought. If there’s a spectrum then that means that anyone whose opinions fall on one end of the spectrum must therefore logically be an extremist (and therefore dangerous and evil). And anyone whose opinions fall somewhere in the centre of the spectrum must logically be a moderate (and therefore a good and reasonable person).
Naturally those who currently dominate the political scene, the liberals and the globalists, present themselves as being in the middle of the spectrum. They believe (or claim to believe) in liberal democracy and what could possibly be more moderate, more centrist and more reasonable than that? Wicked people who disagree with them are either communists (far left) or fascists (far right). Nobody bothers much about demonising communists any more. Communists only exist on American university campuses. It’s those right-wing fascists that need to be disqualified and demonised.
In fact if you think about it liberal democracy is itself a rather extreme political view. Two hundred years ago wise statesmen like Metternich quite rightly considered democracy to be dangerous extremist nonsense. The core principles of liberalism were regarded as being fairly outlandish and certainly unworkable in practice. Liberalism was the doctrine of cranks. Those prejudices have turned out to be quite correct - liberal democracy never has worked and never will work. But people who believe in liberal democracy are not considered to be either far left or far right and therefore by default they are considered, quite wrongly, to be moderates.
And a century ago globalism would have been dismissed as extremist claptrap. It is extremist claptrap. There is nothing remotely moderate about globalism as a political philosophy. It is as extreme as marxism was a hundred years ago.
If you want to find political fanatics today you’ll find them among the ranks of globalists and Social Justice Warriors. The views of the “far right” are by contrast remarkably moderate. Even the few remaining genuine old school hard leftists are moderates compared to the unbridled lunacy of globalists and SJWs.
It all comes down to who gets to apply the labels.