I see some merit to the arguments that Mamdani's methods may undercut his own stated goals. Adding regulation and empowering tenants could reduce capital investments and stall the building of additional affordable housing. Idk, he might fail at this and I'm interested to see how it all turns out. But, the actual criticisms are so dumb. Communism? Since 1965, they've had 7A. The city could use 7A to put an apartment building in a receivership in which the neglectful owner would keep ownership but lose control of operations. The court-appointed receiver would receive the rents and make the required repairs to be compliant with the law. The city would have a lien on the property for the fines and costs (including potential unpaid taxes) and could in theory foreclose on the lien if the owner and the property operations could not make the city whole. Since 1996 (under Giuliani), NYC had a program called Third Party Transfer. By it, the city would foreclose on liens to take properties hopelessly in arrears, remediate them, and then sell them to private properties. Those buyers would usually be non-profits, co-ops, or mission-driven developers. Hundreds of properties entered the program from 1996 to 2019, though not all of them ended with ownership transfer in the end. In 2019, under Bill de Blasio, the program was paused. Since then, the city would hold the liens so that they can get paid from proceeds if the owner ever sells his property. Holding liens means you don't get your money yet and you might never. They also sold some of their liens, but you take a discount when you sell the liens. The Mamdani "seizures" being called communism is essentially just restarting these previously operational and on-the-books programs, taking over operations from bad landlords and foreclosing on properties in arrears. He is putting an emphasis on tenant representation through tenant boards, co-ops, and non-profits, but that's not even new. If this is communism, it's not the boogieman everyone made communism out to be.
That's basically his MO - democratic socialist. He may or may not fail at it, but it's what he does and what he was elected to do. Of course, the confused or intentionally obtuse will say it's communism.