Why? He didn't technically say anything wrong.

I would find it very annoying to be in same situation as him. The point is that its a fact that multi multiculturalism has been taken too far. In all countries and frankly nowhere more than in UK. All kinds of people just make a beeline for UK considering it as their personal bastion

And then they want their own culture and living ways to be applicable there. I don't think that's done.
Just look at the recent case that was turned down. The hindu's were fighting for rights of an open fire burial of their dead. It created an outrage in UK as for them the concept is alien. Same with Muslims. They walk in Burqua's and bring their own culture which will annoy the natives.
I don't see anything wrong in what Flintoff said. He had the guts to say it,, when many can't.