I’m not sure why I’m getting downvoted. I am uninformed, and since that is all I knew I asked in the first place…

You play the "I'm just an ignorant person" character whilst spouting pro-Russia propaganda as if everybody else is an idiot.

This is indicated by how in your words "Ukraine joining NATO" is "an understandable reason for Russia to invade" and yet Russia invading Ukraine in 2014 is not an understandable reason for Ukraine to merelly join NATO - not only is the threat level of "having NATO next door" completelly different from "having a bigger nation next door that already invaded us" not even in the same universe as justifications for action with regards to your next door neightbour go, but actions themselves are hugelly different in terms of impact and even principle:

• Joining NATO is doing what you want with your own territory and doesn't kill people or even cause them to flee.
• Invading your next door neighbour is doing what you want in somebody else's territory, killing people (hundreds of thousand already) and causing even more people to flee (millions).

Or to put things in perpective, you've been spouting all about how you "understand" the reason a murderer gave for murdering his neighbour, which is that "the other guy wanted to invite some friends over to his home".