2. It's a complexe subject. Affirmative action in the US, cast-based quotas in India, etc
Ideally, I would adhere to the french universalist logic which considers that no color or religion-based criteria should be used by any institution. No "sub-groups" in the collectivity. In France, even race/religion-based statistics are forbidden.
But in practice, things are less obvious and these measures can bear good results in highly racialized, non-mixed countries such as the US and..... Brazil (?)