Are you talking about the partition?
During partition, mass migration happened voluntarily with violence relegated to the border regions in Punjab and Bengal (Bangladeshi border or at that time East Pakistan), and a few other major cities like Delhi, and other cities in Pakistan and present day Bangladesh. The violence was perpetrated by Hindus, Muslims and Sikhs, alike toward the other groups. In Muslim majority areas, more Hindus died and in Hindu majority areas more Muslims died.
That said, all 3 groups were guilty of some form of ethnic cleansing to one degree or another, indeed. But they were relegated to border regions.
The majority of Hindus or Muslims in the country however, were not affected.
As for right of return, the majority of Indians do not care if they return. We are not trying to forcefully manage demographics the way Israel is or instituting legal systems that are different for different religious or ethnic groups. They are welcome back.
Criticism or more accurately, abuse of by the KKK of a racial group is racism.
Criticism of a multi-religious, multi-ethnic, pluralistic nation for its policies towards the Palestinians, or criticism of ethno-religious supremacist political movements such as Zionism, are not.