If one holds, as a basic principle, that the government may not inflict any injustices directly, then the fact that there are pre-existing injustices in the real world, while unfortunate, can only be remediated by measures that cannot possibly inflict any injustices themselves (and it must be possible to prove that). Of course, that principle slows the progress of disadvantaged groups to full equality, which is why there's currently an acrimonious debate around whether or not it should continue to be observed.
The ideal situation, of course, is when the economy is working so well that there are good jobs for all qualified applicants, so that ensuring those from a previously discriminated-against group have opportunities doesn't shut anyone else out. Governments have not been doing their job to restore normal economic conditions (those of the 1948-1968 post-war boom), and so they shouldn't be surprised the electorate is now rancorous and is putting demagogues in office. They should have prevented that by doing their job in the first place.
It's not as if any laws of physics would have to be violated to achieve this; we can first go on a binge building a vast number of breeder reactors, and then we will be able to produce enough energy to sustain any level of economic activity likely to be desired.