All laws must be applied to all people living in a country.
They must be applied equally, without regard to religion, race or country of origin.

To invoke 'constitutionality' or democracy in such a discussion requires an understanding of who is who in the zoo and their origins.

Where colonial invasion has been relatively recent (Oz, N & S America, Africa come to mind) the indigenous inhabitants weren't really consulted about the validity of their conventions; most of them were marginalised and repressed instead. Where the colonial invasion was less recent (the UK comes to mind) it seems a bit churlish for the later invaders and their descendants to both ignore their predecessors and repress later arrivals with notions of "laws".

It could even be described as merely a brutal exercise of power "because we could."

Cheers, Rowan