You're myopically selecting a single incident out of a multitude of hostilities and invasions such as https://en.wikipedia.org/wiki/Russo-Georgian_War which by the way included a prototype 'field test' of the disinformation strategy that was later wielded against US and EU with terrifying effectiveness.

I'm sure if one tries hard enough, they can find some kind of justifications for a lot of Russia's actions, but the bigger picture remains unchanged: Russia is a giant dick and most of its neighbours are afraid of it. Hence NATO.