The left does not understand the meaning of the term 'diversity.' Diversity essentially means parts of a whole being different from each other, but still part of the same whole. That is what it inherently means.
However the left looks at it from a perspective where diversity means simply being different. That is not diversity, simply because it is not being diverse. It is only being divergent.
African-Americans, Native-Americans, Irish-Americans, Asian-Americans etc etc etc .....that is diversity. They keep their individual identities, but they still know they are Americans and hence strive for the betterment of the land they call home ....America. After 9-11 it was evident how everyone came together, no hyphens or anything .....simply American.
However, if I start saying that I am not a Kenyan-American but Kenyan, and that I despise the US and it is vile and reprehensible, then by my assertions I cannot claim to be adding to any form of diversity. The least I would be is a hypocrite. The worst ......!
Many (not all ....but definitely a huge number) Muslims do not see themselves as Americans but merely people living in America. That is not diversity ....it is being apart.
Take FR for example. There are all sorts of Freepers. Some gentle, others acid-tongued. Some intelligent, others go on purely by the grace of God. Many have established views and beliefs, and some have some rather 'eclectic and eccentric' political and social views. But at the end of the day we are all Freepers. We all contribute at making FR more diverse.
Now, let's say someone from DU comes to FR as a troll. He will not be adding to any diversity. All he will doing is disrupting and creating schisms.
The Left seems to see diversity as letting everything in, yet the core of the word is different parts of a whole ...but still a whole.