when 100s of barbarians surround a village populated with unarmed, un-prepared people and kill them all, do you call them war? No, It is not war. And it is not "terrorism" as well. Its worse than that, may be "genocide" is a better word. Today, the rest of the world is caught up with these barbarians, so their only option is "terrorism".
Terrorism is assymmetric psychological warfare. It's done by forces who are extremely and utterly outclassed in strength.
You essentially are stretching the definition of terrorism so that you can use the hotter buzzword to demonize them and that period of Indian history.