You *do* know that every horrific oppression came with "reasonable" arguments at the time about how this was supposedly morally correct, right?
Examples:
Pro-slavery people argued that slavery was actually a benefit to the slaves, that slaves were intellectually inferior (with less advanced tech as proof), that freeing the slaves would be actually really cruel and damaging, as they just weren't built for an unguided life.
Anti women's suffrage argued voting wouldn't actually help women as women weren't suffering, that women were "outside of politics" and thus a more unbiased source, that women are incapable of physically enforcing laws they might make, and that men earned votes by serving in war.
Both of these arguments appeal to stuff like harm, rights, justice - all externalized, systematic reasons *divorced from the individual* about why they should be treated differently in culture, about how treating people at the level of groups is a *moral good*.
So obviously the lesson from this is, be wary of arguments that call in systemic enforcement to justify treating people differently based on their group, *even if they appeal to important moral values that you share*, right?
....Right?
Your examples are all groups where being part of isn't a choice. Deriving that the same applies to any group,while disregarding the question if freely chosen or assigned by external factors,seems a little oversimplified?
I am specifically referring to systemic enforcement - I am less convinced that individuals should be forbidden from using group information to make assumptions about members of those groups (chosen or unchosen) without more info.
Even so,let's say I was part of a group that mostly identifies by feeling entitled to randomly stab people with knives,wouldn't you say that making sure we don't follow through with this *does* justify some degree of systemic enforcement?