re: "a disgraced former governor who was forced to resign and is now running as an independent."

[thesquanderer]

Despite not being on the party line on the ballot, he is still campaigning as a Democrat.

In an interview with NBC News' "Meet the Press NOW" earlier this month, Cuomo said that he and Mamdani are like "apples and oranges" and described the Democratic mayoral nominee as "fringe."

"You know, it’s apples and oranges. We couldn’t be more different. I’m a mainstream Democrat. He’s a fringe Democrat,” Cuomo said.

(from https://www.nbcnews.com/politics/elections/democratic-national-committee-zohran-mamdani-endorsement-nyc-mayor-rcna237025 )

He is still seen by people as a Democrat, running against another Democrat, and as that quote shows, that's how he wants it to be seen. And I do think the average voter-on-the-street sees Cuomo as "establishment."

The (correct) perception out there is that a lot of well known people in the party are hesitant to support the Democratic nominee, and one of the best-known Dems in NY is actively campaigning against him.

And while I agree with you that, in general, endorsements don't matter much, I think people's expectations are that the usual public Democratic supporters will support the Democratic nominee. So while no individual endorsement may carry much weight, I think the sum of all the NON-endorsements from those who normally would whole-heartedly endorse the Dem nominee does send a message, i.e. that there's a lot of hesitation about him from within the Democratic establishment. It gives Mamdani another hurdle to overcome.