That's an interesting thought. Maybe I do think that it is better to make everyone a little bit worse off materially to make the distribution more equal. I don't think this is pathological. In somewhat of a paradox what matters most to absolute well-being is our relative material wealth not our absolute wealth. Now, of course, when looked at as a ranking nothing can be done about the fact that some will have more wealth than others. Nothing short of trying to make everyone equal (and no one wants that). But the ranking is not the only thing that matters. There has always been a distribution of wealth but the those at the top have not always had so much more than the median. Making everyone a little worse off materially to make the distribution a bit narrower may make the absolute well-being greater. Also I wonder if right wingers would support a distributionist policy to help the poor and oppressed even if such a policy were certain to be effective. My hunch is that they would not because they are opposed, in principle, to any redistribution.

I did say this: [...] So I agree there are a number of falsifiable beliefs on both sides. But the mere fact of falsifiability doesn't mean the disagreements are easy to resolve, partly for "politics is the mind-killer" type reasons, and partly because it is legitimately difficult to find conclusive experimental evidence for causal claims in the social sciences. I do, however, think there are important value disagreements about how to trade off efficiency and equity between left and right, and I also think your description of the "main value disagreement" is a caricature. I'm pretty sure I could easily come up with socio-political thought experiments where all (non-moral) facts are made explicit, leaving no room for disagreement on them, but where we would still disagree about the best policy, and I assure you I'm not one of the "pathological" egalitarians you describe (although you would probably consider my views pathological for other reasons).