You're still misrepresenting international law, though. It's not as ephemeral as your portray it, most of it is based on existing treaties, declarations, and agreements, and the rest of it is also not arbitrary but rather based on convention and customary procedure among states.
There is a reason why countries like the US and Russia go at great length in arguing that what they do is not violating international law in cases when they are actually breaking it.
Moreover, even those states who occasionally break it most of the time conform with international law and resort to treaties and conflict resolution mechanisms associated with them. It's not as if Russia (or the US, for what it matters) ratify no international agreements at all or always break them or completely ignore international agreements.
Overall, your position is unrealistic and does not reflect the reality of international relations. Countries do not just do whatever they want out of a position of power, and for most part even those that break treaties, agreements, and habitual rules of conduct only do so as an exception to the rule. I can assure you that Russia cares a great deal about being recognized as a rational and reliable actor rather than as a mad rogue state.
What you say about the morality of states (whatever that means, to me the concept is meaningless) is clearly just your personal opinion, so let's ignore that.