The primary relevance of the US position on the attacks, in the India-Pakistan context, is that it points to a continued failure of the Indian diplomatic offensive to "isolate Pakistan internationally".
Look, everyone knows at this point that India does not have (and will not have for another generation at least, assuming a continuation of the current economic growth in both States) the kind of conventional military superiority over Pakistan that would allow the Indian government to "act strong" in front of the electorate by conducting punitive military strikes against Pakistan without suffering an equally punitive Pakistani military retaliation. With that kind of military status-quo, the Indian government, and especially the new Hindu Nationalist Modi government, will need to display some kind of tangible "international diplomatic punishment of Pakistan" to appease its hawkish base and differentiate itself from the preceding Congress led government on the issue of India-Pakistan relations.
Of course this is but the start of the Modi government, and certain events (on the terrorism front especially) can still change the current course of positive engagement between Pakistan and the US, Russia, EU and China (in the latter case, an inability to fulfil the promise of billions in investment in various sectors in Pakistan), but the current trajectory leaves few options for the Modi government outside of overt or covert military action against Pakistan, which in turn will invite an escalatory covert and overt military response from Pakistan, which in turn will hamstring the Modi government's ability to deliver on the economic front domestically. Domestic economic growth is something Modi absolutely has to deliver on if he wants to retain the BJP's electoral primacy for more than one election cycle, so he will have to balance the demands for military escalation from hawks within the BJP with the demands to deliver on the economic front. On the Pakistani side, neutralizing the Indian ability to leverage terrorist groups within Pakistan (TTP, LeJ, BLA, BRA etc.) will demand continued focus on the fight against the TTP in the North West and an elevation of the overt and covert ops against the cells in the 'settled areas'.