Hear me out.
I think there is a simple truth that as long as there is diversity there will be lines in the sand between culture, religion or lack thereof, economic class and the social circles they create, and many other facets in our day to day life.
As long as there is diversity there will be confrontation.
Do those who want to remove religion (or a lack thereof) or cultural "barriers", economic classes, various education levels, also want to destroy diversity?
And should diversity be destroyed?
Thank you for hearing out my abstract mind process.
IMO:
Even if you wanted, you could not destroy diversity. Humans are just diverse, and will always be. That may be good or bad, but it doesn't matter, because it's just how things are.
So the good sides of diversity should be celebrated, encouraged and enjoyed, and the bad sides should be minimized.
When you look at the context of cultural diversity within a given state or society -- which is in which context this term is most often used, and which you probably are hinting at, too --, I'd say there had to be a frame, rules that allow the state and society to function, on which a maximum of people has to agree on.
Only when people are not diverse at all when it comes to agreement to this frame, diversity in all other fields can be a good thing, and one that can be embraced and celebrated.
This frame should IMO be constitutional, classically liberal values along the lines of "your freedom ends where the freedom of someone else begins". Neither the government nor any individual citizen or private actor must violate this principle: To each his own, as long as you don't harm someone else in the process.
It's nice to have a society as diverse as encompassing fundamentalist Christians, proud gays celebrating their gayness, faithful Muslims, leftist slackers, artists of all kinds, work-a-holics, right wing warmongers -- as long as they know that their rules only apply to themselves, and they have no right to force their idea of life on anybody else.
That means fundamentalist Christians and faithful Muslims have to learn that the government is not supposed to legislate morals binding even to non-believers, just like slackers have to learn they are welcome to just enjoy their lifes as they wish as long as they get their money by legal means, and people easily offended have to learn that a different opinion is no reason to feel rightfully offended, i.e. -- and that at any rate, violence is never justified to solve matters of politics or worldview within a society, but there are free and fair elections to do that.
This is the frame there must be no diversity on. A maximum of people has to agree on this frame. If not, diversity becomes chaos and violence.