No, I would not describe him as a terrorist, but a sadly misguided individual.
So, are most Muslims bad Muslims then to read the same information, but choose not to act upon it?
Lets assume for a second that you can equate the use of religion with the use of a political ideal (which I disagree with, but I digress), how the hell would you even do that?
Again, I suggest you read it without making assumptions about it.
Depends on what time period you are looking at.
Which is why it is a popular tool, but you can do multiple things to greatly decrease the chance of success.