You know, the original intent of UN was of an organisation to do exactly this. After the second world war, the determination was made that the no pill is too bitter to prevent the next third reich from coming to existence. And that the free nations will spare no price in blood, nations sovereignty, and economic damage to achieve that.
The UN was then sabotaged in its infancy by the very same major powers who vouched to back it. I will let readers to research by themselves who was the biggest proponent of admitting USSR to UN.
The early history of UN was of it being a Western nations club, and a quite potent body. The later didn't fared well with the same major powers in the West. Look who was the biggest opponent of resolution 377 historically https://en.wikipedia.org/wiki/United_Nations_General_Assembl...
The treaties and decisions of UN can only be binding on the members iff they voluntarily join these treaties. If USSR wasn't admitted to UN, then UN would be even more useless than historically. If UN was designed to be more strict - to require effective, significant delegation/surrender of sovereignty - then even other major powers would not join, and it would also be even more useless than historically.
Theoretically there could be a model of "UN" that would consist of the West trying to impose their decisions on the whole world. But that would require both the will and the ability to actually enforce these decisions despite the cost in blood, and there is neither.
Regarding will, it would have to be sort of like a military aggressive super-NATO - which "the west" was not willing to do; there's a reason why the NATO treaties are strictly as a defensive alliance, and even then limiting the territories which will be defended (so i.e. a military attack on British and French overseas colonies would not trigger any obligations from NATO); and regarding the ability - throughout the Cold War the West was obviously not capable to unilaterally force USSR to do anything, so a super-UN was impossible, and the current UN was the most that was achievable.
Also their participation in the Korean War obviously and a bunch of minor skirmishes.
Its a crude deflection.
One countries atrocities are not an excuse for other to follow their suit
The default position is that a sovereign nation can do as it pleases; if other nations does not like it, they are welcome to try and force it to change with military power - but having nuclear deterrent significantly limits such options.
Since you need essentially voluntary compliance, it makes all sense that any "misbehaving" major nations have a seat on the councils (such as the Human Rights Council), since any decision made without involving them would be just completely worthless empty words.