Something that has been fashionable to complain about in the last few decades is “extremism”. What is actually meant is something that is extremely out of the mainstream, but the problem is that it’s well known that the majority of people can be quite wrong. Indeed, given how recently deep racism was the mainstream in the United States (and analogous things can easily be found elsewhere, such as anti-semitism in Europe), simply accusing people of being a minority is not viable. So this is done under the cover of claiming that the problem isn’t that the person is in a minority position, but that his views are on the extreme of some spectrum, making them wrong, since truth always lies in the middle of all extremes.
The thing is, this is—to put it mildly—extremely stupid.
The truth is not always in the middle. This is very easy to see by just considering cases where no one is a moderate today. Everyone is an extremist about how much slavery should be allowed. Everyone is an extremist on whether the human race should be extinguished (most people hold an extreme ‘no’, some people hold an extreme ‘yes‘, but no one holds a moderate position). You will find exceedingly few moderates on the subject of whether the Jews should be wiped out.
This gets even clearer if you consider cases where no one was ever on the opposing side. Should we build as many nuclear weapons as possible and detonate them over all of the landmasses of the earth? The correct position is not a moderate one between “yes” and “no”. Should we salt all of the farmland on the earth? Should we beat people who go out in public? Should we mandate dragging a 500 pound rock if a person leaves his house? Should rape be legal? Should rape be state-sponsored, with generous bounties paid to rapists?
The correct position on all of these is not moderation.
By the way, I just happened to pick examples where the correct position is an extreme ‘no’. One can easily come up with examples where the correct answer is an extreme ‘yes’: should babies be suffered to live? Should we permit people to breathe air? Should we appreciate beauty? Should we love people? Should we try to be good? Should we be honest?
The correct position on all of these is not moderation, either.
Now, if you point this out to the people who say that the problem is extremism, they will get angry at you because this isn’t what they meant. And, indeed, it’s not. The problem is that it’s what they said. The reason that they’re getting angry is that they don’t like being called out on the fact that they’re lying to you. They are actually complaining about people being outside of the mainstream despite knowing that that isn’t a valid criticism.
Curiously, liars always seem to think it rude to point out that they’re lying.
There is an exception to the above, by the way, and that is what amounts to a heresy. It is always a mistake to take a single virtue (that isn’t the all-encompassing virtue of love, as in agape, the love of God) and to value only it at the expense of all other virtues. Thus courage is good, but not to the exclusion of honesty, mercy, faith, love, etc. Mercy is good, but not to the exclusion of justice, honesty, etc. This is not normally how people use the term “extremism” as a critique, but if they were to, that would be a valid critique. It would be better to criticize this as a heresy, since the idea of a heresy is that it takes one or a few parts of orthodoxy and leaves the rest, and this is what picking a virtue and valuing only it to the exclusion of other virtues is doing. But it is also going to an extreme, and a bad form of doing so, so the word would not be inapplicable.
As I said, that’s not what people normally mean by using “extremism” as a derogative, but if anyone does, my critique above does not apply to them.