I feel like I ought to note that there's no evidence of military activity (that I know of) in the IVC, but certainly evidence of violence: https://libres.uncg.edu/ir/uncg/f/G_Robbins_Schug_Peaceful_2... . I wish it weren't the case, but it seems early Harappan scholars made the same error that early scholars of the Minoans did in concluding that the absence of evidence of violence implied the absence of violence itself. Of course, this doesn't mean that the IVC wasn't a relatively peaceful place compared with places like Sumer or Elam, like you said.