I agree with all that, lucky.
I've just been thinking through some stages of hitting back. When I was bullied at school I eventually hit back, on the bully's head, with a very heavy physics book. Violence. I'm not a violent person, but it was necessary and it worked. She never bullied me again, even got quite friendly. She grew up allright too.
If bullying thugs like Isis attack innocent people and civilisation, which is what they're doing, there comes a point when what/who they are attacking has to hit back, or when we have to hit back on behalf of those innocent people. I think that's what JM is saying. It's the same as stopping Nazi thugs. I don't think either group was or is open to negotiation.
Their violence cannot be justified (which is what the apologistic "we caused it" stance is saying) in my mind, just as IRA violence against innocent people could never be justified even though I sympathised with their cause.