You must read more. That is all I have to say. Read about the causes from all angles. If you always read from one perspective, your understanding will be limited.
And there's no point going into the Khalistan issue here as you didn't pay heed to what I wrote in the Op Bluestar thread.
I know the reasons muslims wanted a seperate nation so did all that. Sikhs always enjoyed special status by British for thier sychophancy in return. They always helped British to crush freedom movement. They wanted same post independence.
Anyways, whatever the reason is doind terrorism using religion with help of enemy nation can never be justified till day of doom.