Leftists who are critical of the left are rare as hen’s teeth. You know the saying: “no friends to the right, no enemies to the left”. Thus any criticism of the left from the left feels like a breath of fresh air to the right. “It’s not just us!” they cry in relief. Of course, that’s the whole point of that maxim, to starve them of their air supply, to deny them the social proof that gives people strength. If people are saying something and nobody else is, they’ll eventually lose heart and shut up. Any leftist who criticizes the left is incredibly harmful, like Glenn Greenwald, Jimmy Dore, etc.