Every riot is caused by an incident that was caused by an incident that was caused by an incident that was caused by an incident, ad infinitum.

The essence is not how and why precisely a riot erupted. The essence is whether India has a government that condones riots.

Ultimately, the essence is that in a working democracy, which India still claims to be, the elected PM should take up the position of being the PM of ALL the people. In this position, the PM is held to clearly pass the message that any riot at all, caused howsoever and directed at whomsoever, is in fact an act of violence against India as a whole.

There is a time for political campaigning and there is a time for compassionate leadership and statesmanship.

For the record: this reply is not mine. Even Kautilya (Chanakya) would have strongly disapproved of the current state affairs:

सृहृद्बंधु स्वामी शरणमुपकारी वर गुरूः

पिता माता भ्राता जगति पुरुषो यः स नृपति ॥

He is a deserving ruler, who is a protector of the orphaned, the refuge of refugees, a guide to the afflicted, protector of the marginalized, support of the unsteady. A deserving ruler is a friend, a relative, a counsellor, a benefactor, a techer, a father, a mother, a brother ... to all.