States that practice torture, slavery, brutal oppression of women, child labor, and other crimes were not condemned when these were standard practices.
Same with ethnic cleansing, conquest, destruction of societies under imperial domination, etc. States that carry out those policies today are condemned, though inadequately, and if backed by the US are scarcely condemned at all, as in the case of Israel, where any condemnation with threat of implementation [of UN resolutions] (which is rare) is instantly vetoed. If the US today were to carry out the practices that established the national territory, there would be worldwide revulsion and condemnation in the West, unlike at the time, when it was well within the horrendous norm.
There has been progress in establishing civilized norms, which shouldn’t be overlooked, though there is obviously a very long way to go.
Contemporary norms were affirmed in the UN Charter — in principle, practice is a different matter. And they are not retrospective, or few would escape censure so harsh that the occasional tapping on the wrist of Israel would be invisible in comparison. There are a few cases of military occupation since those norms were established: Indonesia in East Timor, Morocco in Western Sahara, and Israel’s rule since 1967 in the occupied territories, and in parts of Lebanon for 22 years in violation of Security Council orders. All have been formally condemned. Implementation is determined by power interests.