It is a good thing that de jure discrimination was ended.
But are you claiming de facto discrimination doesn't exist? Do you think the attitudes behind those practices we forbade haven't lingered on? Because if discrimination still does exist, and a lot of people still operate in a racist/sexist mindset, we have a serious problem.
Of course that's not what I'm claiming. Discrimination does exist and against all groups to varying degrees in public and private. I still hold that that is irrelevant to the point that elected officials share their policy positions, people vote based on those positions. Are you saying there are NO politicians who share your view on a topic? That may be the case. Almost certainly no politicians agree with all of your views, and there's always the problem of idealism vs pragmatism when it comes to enacting changes...
How does "more people in group x" solve this problem?