I was just going to post the exact same thing.
That’s why DeSantis is the new Satan.
Calling your opponent "an extremist" is a sort of one-size-fits-all general accusation. It's just a generic label the left-wing media can try to hang around any Republican's neck. If nothing else it can buy time, while the Central Liberal Hive Mind comes up with a more nuanced accusation.
The Left has gone so radically far to the left that just being a normal American is now "extremism," from their point of view. There are plenty of left-wing pundits in the MSM who will have no problem with that label, and who can be counted on to pick up the ball and run with it.
I suppose one way to counter the "extremist" label is to make campaign commercials showing the most newsworthy Democrat positions (BLM, ANTIFA, the riots of 2020, transgender "girls" in girls' locker rooms, etc.), and then a female voice says "and [Dem candidate] calls [GOP candidate] an extremist!"