US has been selling weapons to Pakistan LONG before Afghanistan war. US sold 100 F-86 sabers to Pakistan as early as 1957. You can't pin that one on India. In 1965 war India beat American weaponry used by Pakistan not with Russian but with British weaponry. Indian had close military ties with western bloc (UK and France) as much as Eastern block (USSR). India was non-aligned and US was haughtily riding her moral high horse of leading the free world. You picked the losing side. India won every single war against Pakistan. And emerged the economic winners in Asia. And we all saw how your alliance with Pakistan and China worked out. Now tell me who picked the wrong side.
Again, Cold War strategic calculations drove US foreign policy toward Pakistan. Having Pakistan as an American ally was seen as essential to blocking Soviet and Chinese access to the Indian Ocean. India’s socialism was also at odds with US political and diplomatic concerns.