There are a couple of reasons.
1. The USA provided significant material support to Pakistan prior to and during the Indo-Pakistani wars which were to some extent seen as a cold war proxy conflict between the USA and USSR; this support and military cooperation continues in various forms, so India is naturally wary of American actions in the region. Although the cold war is for the most part over and the relationship between Russia and the USA has warmed substantially, India and Pakistan are still constantly at each other's throats; fatal border clashes are quite common.
2. India is a democracy but it is a country that is still plagued by a socially ingrained class system that just won't die. Corruption, strife, and malnutrition are rampant; while literacy is not. Deflecting blame onto distant, untouchable, and largely uncaring foreign entities is a tried and true method of bolstering domestic support.
3. India is poised to be a potential superpower in the near future, so they're naturally trying to shore up nationalism and a we-can-do-it-ourselves attitude. Conveniently rewriting history, or omitting important contextual information is in no way an Indian invention.