The people "on the left" excited by Kennedy running, are the same people "on the left" who have complicated opinions about why Putin was right to invade, and the same people "on the left" who thought we should hear QAnon out about vaccines, and the same people "on the left" who thought we should "work with" *checks notes* fascist militia Boogaloo Bois to, something something.
Maybe they just aren't "people on the left" at all. And it's the exact same people, every time; curious that.