I think part of that is the fact that the most densely populated cities are democrat. I don't think it could be shown that being democrat led alone was the cause of the worst rates. NYC is one of the most crowded places on the planet and a huge travel hub. Not defending what NYC did though, I don't know enough to say what they did right and what they did wrong.
Trump made quite a few inexcusable mistakest in my opinion however he also did take a lot of flack that he didn't deserve as well. Pandemic response was really much more of a state and local thing than it is a national response. The president can do a few things to help out but I think the real decision makers are the governors. Governors are much better situated to direct a response based on the situation in the area.
Katrina hit a state that was run by a Democrat governor, and New Orleans was under a Democrat Mayor. The governor refused FEMA resources and assistance for a week, while Bush had truckloads of relief supplies sitting at the LA border.
Yet, somehow, the pain in LA was Bush's fault.
Same for the Dem governors and mayors under pandemic decisions. They got 100% support from Trump's administration including facilities and personnel. if they needed Trump to run the pandemic response for any reason, they only had to ask.
We all know that high density living arrangements invite crime, disease, and other problems. If NYC was not ready for the pandemic, that's their problem, not Trump's. It's not like a few million extra people snuck into the state/city a week before the pandemic hit. They should be preparing for the next medical catastrophe every quarter. Was Giuliani prepared for 9/11? No, but he had the experience and wisdom to direct resources as needed to manage the catastrophe as best he could. Many lessons were learned, like making sure first responders' radios work inside these buildings now. Most didn't get the message to evacuate the remaining tower after the first tower fell.
Anyway, if NYC can't handle the population density they have, then they need to look into ways to improve that or reduce the density. Anything less is their negligence. We've had several pandemics since I've been an adult. NYC should not treat them as a "rarity".