This has a lot to do with movements on the Left being generally antagonistic toward hierarchy - it’s been a feature since the late 1950s.

It’s helpful in that it allows organizations to be more flexible, allows more grassroots participation, is more democratic, and enables local chapters to adapt to local needs.

But, yes, from a stability, consistency, and messaging standpoint, it’s an absolute nightmare.

IMO, historically, it’s the center left moderates that used hierarchical organization that generally got shit done, but it’s the wild-ass chaos factories of the further left that held them accountable and kept them from compromising more than they already did. Both were and are valuable.