You know, sometimes I want to disagree when someone here blames stuff like this on "diversity".
If (legal) immigrants want to remember their heritage, continue cooking the traditional foods of their past, wear the traditional clothing styles of their heritage, continue to celebrate on the traditional holidays of their native land, even keep and speak their native tongue as a second language, we can all share in the diversity. Enjoy the food, the pageantry, learn a bit about the customs, even learn how to say please and thank you in that language....maybe how to order a couple of beers...
But when they would start to refer to soldiers of the enemies the US as "their dead", it be comes clear they have not immigrated with the intentions of becoming citizens of their new home. The British Soldiers (or US Soldiers) should be their soldiers and their dead should be the British killed by Muslim terrorists.
Lack of assimilation and, surely, the lack of any intent to assimilate is the problem, not diversity.