Abu Hamza was preaching or inciting violence as do many of these other preachers. I have no idea where you got the idea that I am taking an issue with Muslim teachers saying things I don't like as I certainly did not say this.
I was am talking about the ones that incite violence, glory in the acts of barbarism by so called fundamentalists. Hamza was doing it in the streets for long enough with nothing more than a slap on the wrist. and did it for ten years unless I missed something somewhere.
The laws as you say may well be there but tended to be used primarily against supposed Islamphobic acts or utterances but rarely against the Muslim preachers/teachers.
I think Hamza trod a fine line and annoyed a lot of people but my memory is sketchy as to what he in particular actually said and I don't really want to lose an afternoon reading it.
I agree that we do need to campaign for existing laws to be used as they were intended, as opposed to rushing through new ones with far too broad a reach. Someone being sent death threats on Twitter doesn't need a new "don't send people death threats on Twitter" law, because it ends up being a "if someone sees something on Twitter that they don't like then it will take up some police time" law.