Why staunch opponents unanimous on caste-based census?

The Centre’s decision not to enumerate the population according to caste as both the allies and the opponents of the National Democratic Alliance have been demanding is unlikely to make the debate disappear. Instead, its intransigence could make the Centre’s opponents further dig in their heels. Census on the basis of caste, on which Nitish Kumar and Tejashwi Yadav's stand is one, then does the stand become one with the opponents only when there is concern about their own future in politics. But why are the staunch opponents unanimous on the caste-based census? Watch this video.