The UN has never had any control over any country. It has has only ever been designated a talking shop where countries can get an understanding of each other. They may have voted a consensus on decisions, but that is by agreement not enforcement. If we had a body that could dictate morality to any country, then we would not need any country with a military.

Has it ever been a facade?

Pretty sure the UN has always been seen as a limp-dick entity that only exists so nations can talk and the Security Council can do what it wants.