Well if that's is the case, then there's no point in having an organization like the UN then is there if countries are going to just do what they want anyway?
Didn't the UN also say that the US invasion of Grenada unlawful aswell but that still went ahead? It kind of makes a mockery of if it was unlawful or not because countries might say something but then just let it happen anyway.
The UN (well, member countries) would do as much as they can to avoid confrontation.
You're right, what is the point of them?
The members that make it up are probably more worried about state of the global markets than the state of sovereignties of countries.
I'm sure though if one of the bigger members were attacked it would take a bit more action