I'm pretty sure India would have had a violent movement too if WW2 hadn't happened and Indians had better access to firearms and stuff. Violence was less of an option because the British government deliberately ensured that the locals were suppressed. Whereas in the U.S. the British were exploitative of the colonies, but they did not suppress the people (until the movement started); after all, those were their own people.
We did, in fact, have a violent movement, in 1857, just that it didn't work out too well.
I don't think that "Indians are less violent" is really an argument to be made here.
That's quite anecdotal at best. My experience has not been the same, I've seen ample violent elements in both places. Indians are generally subtler in our social cues, and that might make Americans "louder" (which feels like aggression), but certainly not more violent.
It also might matter which area of either country you've lived in. Boston(-ish) and Mumbai here.
An acceptable argument for India being more nonviolent would be the entire NAM movement among other initiatives, but there are still many, many other reasons why India's nonviolent independence movement worked -- Indians being nonviolent, if true, would be a small contributor to it, not the main reason. Besides, like I said, we had a violent independence movement and failed. Technically, two, if you count the INA, which actually managed to liberate many areas.
Also, this is not justice & anti-freedom.
People need to understand that issues are NOT black and white, and that "the thin end of the wedge" often needs to be broached in order to benefit wider society.
Plugging everyone into the matrix will also save lives.
The truth that the NSA is massively spying was hidden for a very long time (or rather: Hardly anybody really believed those who told the truth).