Yes, Ashoka the Great attacked the state of Kalinga, with much bloodshed. This war is said to have made Ashoka a Buddhist. I never said that Indian kings did not engage in wars, they did. Still even in this, India there was real rules followed, not always but much of the time.
"Whereas among other nations it is usual, in the contests of war, to ravage the soil and thus to reduce it to an uncultivated waste, among the Indians, on the contrary, by whom husbandmen are regarded as a class that is sacred and inviolable, the tillers of the soil, even when battle is raging in their neighborhood, are undisturbed by any sense of danger, for the combatants on either side in waging the conflict make carnage of each other, but allow those engaged in husbandry to remain quite unmolested." - 4th century B.C. (the greek) Megasthenes
Chinese Buddhist pilgrim Hiuen Tsiang said that there were and wars in the 7th century A.D. but the farmers might be seen quietly pursuing their work, while wars go on all around -" perhaps ploughing, gathering for crops, pruning the trees, or reaping the harvest."
Still this has nothing to do with Hindu tolerance only rules of war.