Hackers have been around for awhile, at least since the Internet came out. Hackers can cause many problems through computers, and are dangerous. Hackers do not use violence, but do strike terror to the victims they hit and as in the movie "Hackers" we can see that a hacker can cause deaths, some hackers are not terrorists, depends on the hacker.
Webster's defines terrorists as someone who uses terror and violence to intimidate. Most hackers do not use violence but do strike terror into their victims. When a hacker changes someone's web site around or infects someone with a virus, they do invoke terror, so the can be called a terrorist. .
Hackers can cause death through computer hacking. Lets say they turn off all street lights in a city, people could get into a accident and die. They could also hack into other departments and cause havoc. .
However do all hackers strike terror, if they do not technically they are not terrorists. One solution to this would be splitting hackers into two groups. Terrorist hackers and then just regular annoying hackers. Terrorist hackers cause terror or violence, through viruses or messing around in someone's web site. Regular hackers would be hackers who would change a word on someone's web site or something of that nature that wouldn't invoke terror just be annoying. .
The point of this is, it just depends on the hacker to classify him/her as a terrorist. You can not classify all hackers terrorists since they could not all be. There should be two categories they could split hackers into. Minor hacking jobs such as changing words might not cause terror, so can not be classified as terrorism. However when you invoke terror or violence, you are a terrorist hacker. If you label all hackers terrorists it is like calling all Afghanistan citizens part of Al Qeida, since not all of them are part of Al Qeida or terrorists. So it all depends on the hacker.