Internationally everything is up for grabs like raw meat is for dogs. Morality and law is a shaky luxury enjoyed within the confines of free nations.
So, every country must protect its turf in the best way they know how. That starts by protecting its borders. If a country can make a grab for another country, and it wants to pay the price in blood, then they will do it. Dictators don't mind paying the price for aggression in blood, if it is the blood of their subjects, and the subjects have no way to resist.
"The first casualty of war is truth." Propaganda is psychological warfare that abounds everywhere and takes all kinds of forms. Aggressors use propaganda to weaken and soften resistance so they can achieve odious political goals without having to use so much of their subjects blood.
Russia is a rogue nation, and always has been, even before Stalin and the others. It will take whatever it can get away with, but Russia is not the only one.
International Law sounds good, but it is nearly non existent, especially with the United Nations which has human rights violators on human rights committees. The U.N. is phony baloney.
The fact is, internationally everything is up for grabs, and the morality within countries borders does not hold outside the borders. Strong cultures devour weaker cultures, and not only militarily but in all other respects.