Not all terrorists are Islamists neither do all Islamist are terrorists. But Islamist have a very radical political orientation and radicality often leads to violence.
When it comes to Muslims, well, of course the question is silly. We all know most Muslims just want to leave in peace and dignity.
What can i add ?
Human beings are violent, civilized or less civilized people are violent. Our race is a race of super-predator which suck up dry everthing on this planet and Human individuals will continue to predate other human individuals one way or the other.
It's good to believe in something greater, but at the end of the day, Muslim or not, we are only humans, with a human nature.
Not all Muslims are terrorists but even those who are not terrorists, I have seen them to be very pleased when these terrorists and other unfortunate events happen to the western countries. That means they sympathize with the cause of these terrorist groups in the first place.
I suppose this is partly true (and partly wrong since most Muslims do not sympathize with blind violence) because of revanchism against Europeans. Which is understandable but to be honest it's the mongols who destroyed the Islamic civilization, Europeans did only came after a long time after that to do what they used to do, compete with each other for global power.