The left calling the right "insane"

First, is calling people "evil" prima facie evidence of insanity?

I think not.

Now let us consider a screed published at NY Magazine: 

https://nymag.com/intelligencer/2020/06/michael-flynn-op-ed-insane-national-security-adviser-trump.html

Its author describes Michael Flynn as "insane".

And what is his evidence for that accusation?

Evidently it is that 

Flynn describes certain trends in our society as being evil.

Now, the definition of "evil" certainly depends on the observer.

But to ascribe insanity to anyone who uses that term?

That only shows how the left has politicized the definition of insanity.