Does being Jewish place him beyond them realm of criticism?

Also, thank you for the clarification.

Respectfully however, regarding "rat" I've never heard of that, my best friend has never heard of that, and my business partner has never heard of that, his sister has never heard of that (all three Jewish).

Wikipedia has never heard of that https://en.wikipedia.org/wiki/List_of_ethnic_slurs#R

The Racial Slurs Database has never heard of that.

http://www.rsdb.org/race/jews

DBedia has never heard of that:

https://dbpedia.org/page/List_of_ethnic_slurs

fact-index has never heard of that:

http://www.fact-index.com/l/li/list_of_ethnic_slurs.html

Given the lack of knowledge of this trope, I'd say it's safe to assume Tucker Carlson has never heard of that either.

Moreover, "rat" is a common trope for all humans used all the time.

I could only find one article that vaguely linked this to a term used in Germany in the early 1900 but didn't present any evidence.

Not that my or anyone else ignorance on the topic is any indication of validity or otherwise, however, it's hard to say a tope used by countless people to label countless other people regardless of ethnicity or race worldwide, is what Carlson intended, noting that he didn't even say that, he said "rat-like".

Maybe he was, I have no clue, but at face value it's a difficult argument to side with.