The author’s point is that Newsom calling Trump a Socialist as an attack on Trump is just Red Scare rhetoric, and it’s ‘unfortunate’ that Trump is not a Socialist, because if he were he’d be pursuing fewer horrible (Capitalist and Authoritarian) policies. The author is not actually lamenting Trump not being a Socialist, he’s disavowing his views.

This is both a silly way to criticize Trump, and a slander against socialism itself.

I mean, I pretty regularly have to debunk the idea that Hitler was a leftist. My dad firmly believes it, because “he was anti-gun and hated freedom, and called himself a national Socialist!”

I’ve explained, until I’m blue in the face, that restricting freedom is right-wing, yes even restricting gun rights can be right-wing, and that Hitler deliberately chose the name “National Socialist” to fool leftists into coming ti meetings - like he straight up admits that in Mein Kampf.
My dad is not somebody who ever learns new information or changes his mind easily, though, so I’ll probably never successfully convince him that nazism was a right wing movement and not even slightly leftist.