"I think you'll find that there is no such thing as a "Christian terrorist", not in the same sense as there are Muslim terrorists. The IRA terrorists were not looking to impose a religious state upon the UK."
When people are blowing up things in your capital city, I'm not sure that whatever distinction you are trying to make here has any practical value.
IIRC the IRA always used to call the police and tell them where the bombs were before they went off, so that people would not be killed by them. Makes a big difference to the people who weren't killed, I'd wager.
The "Christians" you are referring to were politically motivated. The Muslims are motivated by their religion.