Is Diversity our Strength?

I remember reading a while back about a Canadian Province that changed its traditional motto (Latin, if memory serves) to the multi-cultural mantra "Diversity is our Strength."  
This is, I would posit, true in some senses or scenarios, but is not always true.  Nevertheless it is believed without question - sometimes in spite of the evidence - as an article of faith in the "secular/progressive religion" that is so prominent in our culture (and even more so in Canada, from what I can gather).

I've just lived through a denominational split that was caused by... well... diversity.  We had a diversity, even a divergence, of beliefs and priorities: We did not all believe the same things about God, Scripture, or Sin; We were not "on the same page"; we could not walk together because we did not intend to walk in the same direction.  If we had had a little less "diversity" and a little more "sameness" or commonality, maybe the United Methodist Church would not have split.  

Though "diversity is our strength" is the kind of thing you'd hear at meetings and church conferences; it is precisely what killed our ability to work together cohesively.

Of course, there is another kind of diversity that is a strength, as the Scripture affirms: different members of the body bring different spiritual gifts, skills, experiences, to the work of the Church, and the whole is stronger because of it.  There is a diversity of gifts and even backgrounds, but a common Lord, a common mission, a common faith that shapes a common worldview: One Body, One Spirit, One Lord, One Faith, One Baptism...  That God-given diversity is held together by a transcendent Source of unity.  That is the Biblical vision.  There is a Commonality that makes the diversity "work."

But what about in secular society?  Is Diversity our strength?  
The sociological evidence seems to indicate that the answer is "No."  I remember reading about this from Putnam's research years ago (that gets mentioned in this video) and I was hesitant to even share those articles online, because I thought I might get pushback for even suggesting that - just maybe - this "article of faith" in our secular culture might not be correct after all (and I did get some pushback when I shared the findings on social media).

Here is a video from a British conservative talking about this in light of the highly polarized situation.  I think the video does a good job raising the questions: how much "sameness" or "commonality" do you need for diversity to work?  I think the distinction he makes between a multi-racial society that shares a common culture and a multi-cultural society is an important one to ponder.