Is "Fredo" an insult to Italian-Americans?

In my estimation, it all amounts to nothing more than an emotionally-driven burst of anger and frustration. Nothing worth parsing word-for-word.

[“Fredo“] is like the n-word for us.

That's a gross exaggeration. The n-word is used to dehumanize, ridicule and oppress black people. "Fredo" just means the dumb brother.

Cuomo is also being a bit hypocritical having previously, in jest, applied the term to himself.

Chris Cuomo once referred to himself as ‘Fredo’ in radio interview:

HOST: “There is a group of people — politicos — who always hint they might run, but not necessarily plunge all the way, and they are members of la Cuomo.”

CUOMO: “Who am I, then, Fredo?” Cuomo asked in response.

HOST: “Yes, exactly,” Sliwa said. “So you better be careful that your brother Andrew doesn’t kiss you on both cheeks and then all of a sudden they take you out on the middle of the lake and where’s Chris?”

CUOMO: “He kisses me plenty because he’s a great big brother,” Cuomo said.

Who knows what motivated his outburst, but one thing's for sure: "Fredo" can be insulting (having the impact of the words "fool" or "weak"), but it's not nearly as bad as it gets (like using the n-word).

I don't think it's "Fredo" specifically that's the insult. Calling someone by a name that's stereotypically associated with their ethnicity is likely to be viewed as racism. So he would have a similar problem if he called him "Luigi" ("Mario" might work for others, but not him, because that's his father's and son's actual names), called an Arab "Muhammed", or called a Mexican "Juan". This type of name-calling conflates all members of the ethnicity, which is practically the definition of racism, although I don't think it's considered as bad as using terms related to stereotyped activities (e.g. "spear-chucker" for black men).

However, Fredo may be insulting in multiple ways. Not only is it a stereotypical name, but it's also a weak character in a movie that emphasizes another stereotype, that Italian-Americans are gangsters.

However, I don't think it's an established, idiomatic insult like the N-word. I think Cuomo was exaggerating when he said that this was like the N-word to Italian-Americans. From Vox.com:

But Cuomo is being disingenuous at best when he says that Fredo is an insult that’s equivalent to the n-word. (In a statement of support for Cuomo, CNN also characterized the name as an “ethnic slur.”) The latter term has a lengthy and well-trod history as a racist insult, an unambiguous pejorative against black people when used by non-black people. The former is a reference to a pop cultural character from books published in the 1960s and movie adaptations produced the following decade. One is a degrading slur meant to dehumanize the target; the other is a metaphor with unflattering connotations: that the target bears a similarity to a character infamous for his lack of integrity.