North East is nearer to China and Bangladesh. This could be one reason. Another reason is the backwardness which is comparatively more in North East than any other part of India. Frustration and agitation is more among peoples. They kill first and then they talk.
I don't think that residents in North East are frustrated. They live well. They are not very ambitious and are happy as they are. There is no dowry system in most tribal area. They will spend not so lavishly on marriages and other occasions like other places. There is very less corruption also.
The issue is that they are alienated from rest of India. There is need to integrate them.
As regards the current panic among N.E. persons, Govt. blames Pakistan who is in denial mood. Government is ready with evidence.
Twitter is also villain in the current crisis.
http://news.oneindia.in/2012/08/21/twitter-to-face-the-wrath-of-indian-govt-on-ne-messages-1057020.html