Sure, call those Sikhs who did those crimes 30 years ago terrorists.
But that doesn't mean Nijjar is automatically a terrorist any more than Modi is a terrorist because of Hindu nationalist violence, which is a bigger issue and happening now.
Why do you give Modi a pass for fomenting violence through nationalism?
Per the link I gave you, there were attacks even in the 2020s, and even though those attacks are minimal today - attacks against people, are attacks against people. It does not change the fact that they are terrorist. Would you apply the same logic to Al-Qaeda if they were to claim that since they did 9/11 more than 22 years ago, they are not terrorists? This is not a good line of reasoning on your end.
If Nijjar was just a Sikh who supported the Khalistani movement, and engaged in protest, then yes, he would not have been, and should not be considered a terrorist. Is India after every Sikh who protests on the streets of Canada? No. But Nijjar formed a militant group called "Khalistan Tiger Force" and is implicated in attacks in India which is why he is a terrorist. Its immaterial if Frankfooter believes the Indian authorities on these allegations. The fact is those Indian authorities are the experts in this field, deal with it on an everyday basis, keep Indians in India safe and know more about this than you or I, so yes, I will take them at their word.
I am not giving Modi a pass. I am saying he is responsible and should take ownership for Hindu/Muslim violence in the country and create harmony.
But I am also trying to inform you, that Hindu/Muslim conflicts are not something that Modi created. They have always existed. Even before India was formed. Hindu/Muslim violence in India is not so much about cultural divisions or racism. It is more about retaliation (as was the case in 2002), or about religious property (as was the case with the Babri Masjid demolition and the subsequent riots).
In my opinion, there is far less religious violence and far less caste violence in India, today than when I was growing up. A large part of my family lives in India. We are minorities. We are a multi-religious family. We are lower caste. Why do we feel safe, despite Modi? This whole, Modi is fomenting violence etc., is a western media narrative. I am not saying there is absolutely no violence. But anything you have heard about - riots, lynching of Muslims for possession of beef, attacks on couples who celebrate valentines day because they are tarnishing Indian culture - you name it. They have happened since I could understand things. But they have also reduced in frequency today.
As for Hindu Nationalists, the majority of them, who are regular citizens of India, support Modi for his economic policies and national accomplishments. That is all Indians care about. Economic prosperity, national pride and achievements. They don't support Modi because they are rabidly nationalistic and hateful of minorities. The ones who are like that, who join RSS, VHP and other Hindu extremist groups are a minority of people.
So given all this, and given the fact Modi is democratically elected and has a simple majority in Parliament, calling him a "terrorist" is not a well thought out argument. This is where internet Pakistanis and other trolls come in. They basically make these thoughtless comments to get a reaction out of people.