I think you need to see the bigger picture.
Global Muslim population: 2,100,000,000.
IS members: 30,000.
That's a very low representation of "Muslims".
Does every Englishman share responsibility for Jimmy Saville and chums?
Where did you get that 30k figure from? Wikipedia estimates their strength at more like 80k-90k but that's only those who are actually fighting in Iraq and Syria. They have considerable support in other countries including the UK.
It's not about responsibility here, it's about tolerating and allowing unpleasant and undesirable behaviour take root and flourish within your environment. On Jimmy Saville it's true that his behaviour was tolerated by the establishment and so the people who knew or had grounds for suspicion and did nothing (especially the police) are now facing some tough questions and the system is being changed so that hopefully another Saville situation will not happen in future.
