This is more social philosophy than political so that's why it's here.
The value of diversity is in providing perspective, from which wisdom springs.
The more political use of the word means the opposite of solidarity. Which is more valuable? The countries which are most successful are most homogeneous, n'est-ce pas? Clearly we need access to a variety of view-points even just to double-check ourselves if we're right. How can we have meaningful access to diversity without the apparently inherent divisiveness? Is it as simple as "orthodox in certain situations and heterodox in others"? What is the meaningful distinction that can be compromised on? Is there a better way to frame the problem?