Its rotten identity politics that 'state multiculturalism' inculcates that is the main problem.
Everything stems from that.
Pretty much. If culture means clothing, music, food ... even these are impacted by core values. Core values of a modern, with it, Indian from Bangalore is exactly the same as an average Britain. That Indian will party, drink, wear clothes showing a bit of flesh (if a woman) and try pork (if not vegetarian). But take a hard-line or fairly conservative Muslim from Bangladesh, Pakistan, Nigeria or some Arab state then it impacts all these more tangible things such as clothes, food, music, etc. And unfortunately, it can run on several generations within Britain as we see today.
Thankfully, there are modern Bangladeshi, Pakistani and Nigerians who live by British values by default - just not enough of them, say, compared to the Indian demographic.