When I think about multiculturalism I often think about democracy; both concepts value pluralism and consensus, both are high-ranking values in my personal preferences and both tend to disappoint when observed in their real world version.
Democracy and multiculturalism are also in tension with the idea of progress; if you believe that there is a right answer to any given question, voting on it or sitting and listening to others with opposing views seems like a waste of time.
We see very little progress (according to our own beliefs), we get tired with the long, boring slog of consensus-building and then -like most tired people – we succumb to temptation. With democracy, the temptation is to believe in the myth of the benevolent autocrat. With multiculturalism, we are tempted to believe that the views commonly held by people we respect are universal and unimpeachable.
I will agree with this: democracy and multiculturalism would be a waste of time if we knew what the right way to govern or live was. But of course, we don’t really understand these things yet. We may know a good outcome when we see it, but it is pretty evident that we can’t yet replicate these good outcomes or improve on them systematically. If the best my auto mechanic could do is tell me when my car is running OK and when it is on fire I would probably not think too highly of his expertise in auto repair.
It is in light of this ignorance and uncertainty that the virtue of democracy and multiculturalism becomes evident: if you don’t know what the right answer is, a good approach is to focus on the process for finding it*. You try to not rule out any possible answer, no matter how unpleasant, because you want to make progress. Consultation and consensus-building are frustratingly slow, but this is a feature of the system, not a bug. Given that the stakes of society-building are so high, it is much more important to avoid catastrophic outcomes than to move faster.
I believe in progress and therefore also in objective reality in some sense. I get as frustrated as anyone when people continue to question well-established findings. But to abandon respectful, reasoned debate out of frustration with those who refuse to engage with it is to destroy what got us this far in the first place.
*If you believe that there is no right answer to these things, multiculturalism and democracy seem to make even more sense vs. the alternative.