Values have a hierarchy. You can't (effectively) agree to painting everything the color blue, if you can't agree what the color blue is.
And you will run into a very similar issue when everyone starts objecting to the pink you have spread everywhere, despite supposedly agreeing to the color scheme.
You seem to be saying that people can't paint together unless everyone agrees on who holds the brush, what brand of brush is used, and what everyone's broader philosophy of painting is.
But then you go on to describe exactly what @Brendinooo described, just under the guise of your system of "value hierarchy." The problem is that you can always default to "our values are hierarchically misaligned" and then never have to do any coalition building ever.
So how do you solve that? Because it seems that you can't.
This part is too broad.
Hierarchical values are just that. Not wholesale. We call that nonsense, e.g. I believe pigs can fly, therefore the sky is red. They are making an ontological error.
But this seems wrong because people of different creeds and value systems do stuff together all the time. Or am I misunderstanding your point? What I understand @Brendinooo to be saying is: "we may not share the same moral framework (or value hierarchy, using your term), but we do agree on X, so let's do X."
By design. Activists and left-wingers in general enjoy losing and being underdogs and infighting constantly
It's per the usual for extremist ideologies, chock full of hypocrisy and nonsense.
Note that, I have no problem with conservative or liberal value systems...