To be blunt: Islamic invaders to the Indian subcontinent were by and large iconoclastic, at best intolerant and at worst genocidal (by forced conversions, marriages, outright murder, etc) of the native Dharmic (read: Hindu, Buddhist, and Jain) population, and burned down, looted, and deconstructed Hindu and Buddhist places of worship to construct their own mosques on top of said ruins.
The India-Pakistan debacle today is an extension of a nearly millennium-long Hindu-Muslim feud.
The burning of Nalanda University (whether or not it is a 'university' is an orthogonal matter) is another facet in this feud. The decline of Buddhism in the late classical era in the Indian subcontinent—already on a somewhat downhill slope, due to Hinduism co-opting much Buddhist thought, and in general being more popular and accessible than the ascetic demands of monastic Buddhism—was drastically accelerated by the Islamic incursions into the Indian subcontinent.
The Ayodhya mosque-temple riots are another facet of this clash. Western commentators glibly say 'Hindus are anti-Muslim'. The issue in India is so much more nuanced than that; there is bad blood on both sides going back a thousand years. Islam cannot escape from these charges: the religion is fundamentally intolerant of non-Abrahamic ones, especially ones with liberal iconography (like Hinduism and Buddhism).
There is a reason why (most of) the oldest and largest Hindu temples are in South India, which mostly escaped from the period of Muslim rule relatively unscathed. There are (possibly apocryphal) stories about how the idols at several temples (such as the one in Srirangam, Trichy) were relocated to mountain redoubts to prevent them being stolen and melted down by 'the invaders'.
The destruction of Buddhist iconography by Islam (or its followers) continues to this day: the Bamyan Buddhas in Afghanistan were blown up by the Taliban in 2001.