Is he? I thought he'd always claimed to be a democratic socialist. What has he said or done that makes him a communist? I only see a lot of other people labelling him as one as a lazy adhom.
It's not communism to support public-owned public services, even public-owned competitive services where no commercial competition exists. Capitalism in tight spaces, creates monopolies and market quirks that harm consumers, harm renters, harms tourists. These harms are toxic to NYC. He's right to address them.