Ozy (and others) talk about fundamental value differences as a barrier to cooperation.

On their model (as I understand it) there are at least two kinds of disagreement. In the first, people share values but disagree about facts. For example, you and I may both want to help the Third World. But you believe foreign aid helps the Third World, and I believe it props up corrupt governments and discourages economic self-sufficiency. We should remain allies while investigating the true effect of foreign aid, after which our disagreement will disappear.

In the second, you and I have fundamentally different values. Perhaps you want to help the Third World, but I believe that a country should only look after its own citizens. In this case there's nothing to be done. You consider me a heartless monster who wants foreigners to starve, and I consider you a heartless monster who wants to steal from my neighbors to support random people halfway across the world. While we can agree not to have a civil war for pragmatic reasons, we shouldn't mince words and pretend not to be enemies. Ozy writes (liberally edited, read the original):

From a conservative perspective, I am an incomprehensible moral mutant…however, from my perspective, conservatives are perfectly willing to sacrifice things that actually matter in the world– justice, equality, happiness, an end to suffering– in order to suck up to unjust authority or help the wealthy and undeserving or keep people from having sex lives they think are gross.

There is, I feel, opportunity for compromise. An outright war would be unpleasant for everyone…And yet, fundamentally… it's not true that conservatives as a group are working for the same goals as I am but simply have different ideas of how to pursue it…my read of the psychological evidence is that, from my value system, about half the country is evil and it is in my self-interest to shame the expression of their values, indoctrinate their children, and work for a future where their values are no longer represented on this Earth. So it goes.

And from the subreddit comment by GCUPokeItWithAStick:

I do think that at a minimum, if you believe that one person's interests are intrinsically more important than another's (or as the more sophisticated versions play out, that ethics is agent-relative), then something has gone fundamentally wrong, and this, I think, is the core of the distinction between left and right. Being a rightist in this sense is totally indefensible, and a sign that yes, you should give up on attempting to ascertain any sort of moral truth, because you can't do it.

I will give this position its due: I agree with the fact/value distinction. I agree it's conceptually very clear what we're doing when we try to convince someone with our same values of a factual truth, and confusing and maybe impossible to change someone's values.