Working together doesn't mean we have to pretend our allies have no issues.
Newsom doesn't meaningfully resist fascism and his brand of politics are a major part of why we're here. Yeah, I'll stand by him while he's fighting, but that doesn't mean we can't criticize him.
We can't afford to see him as a true ally. He will abandon everything we're fighting for if it benefits him. A tiny percent of leftists criticizing him online amongst themselves will have no impact on how successfully the fascists are able to seize control.
I'm out there alongside liberals who hate most of what I believe, we can be open about that while still working together. We have a common enemy that needs to be stopped.
It means working with people you don't like but it doesn't mean we have to pretend they're perfect, or even good.
The solution to the left cannibalizing itself isn't to ignore issue with people, it's to acknowledge those issues and seek out what we can work together on. Random online leftists aren't meaningfully getting in the way by criticizing him, I'd argue it's important so we keep in mind where he's an ally and where he's an enemy.