"Our society has given so much ...."
the flaw in that statement is that "out" society is also "their" society. Society is all inclusive, it's not something that is frozen in aspic. So the traditional British values that made what was "our" society such an attractive and welcoming place have been altered to include the non-British values of those we welcomed in
Why do we expect everyone who comes to live in the UK will do so complete with a fully-fledged set of liberal British values? It's a ridiculously naive expectation. And you cannot educate people in British values as the PC cultural Marxists insist that everyone's culture and values are as valid as everyone else's. So people come with very non British values that remain unchallenged and our Glorious Leader Cameron instructs us to "integrate more with Muslims".
We seem to have reached the stage in this country where our laws are optional. No Social Services / Police investigation of pregnancies under the statutory consent age, totally blinkered approach to Rotherham, etc. It's got to the stage where unelected public officials are now deciding whether the law of the land is actually worth implementing and who spend their time investigating Tweeters who have dared to call someone "fat".
We have totally and utterly lost the plot.