And is that a bad thing?
Diversity of thought is not bad at all.

You are from India, right?
Well... diversity is not that bad if all the countries are willing to accept it. How many Africans and Arabs are there in India? First accept a few million Africans in India, and then we can have a discussion about forcing diversity in European nations.
That is kind of irrelevant. After you accept immigrants, you want them to adopt the British culture (including the number of children they bear!). The immigrants from Pakistan and Bangladesh did play their role in plugging man power gaps at mills.
India may not be a great example, but it does pull its weight on accepting refugees (especially from its neighbours like Bangladesh and Sri Lanka). I doubt if any of the Syrian refugees would choose India over Europe.