It's fairly simple, actually. Both US and USSR were doing all they can to expand their sphere of influence. This, rather symmetrically, involved invasions, providing military "consultancy" and weapons, coups, etc. Both sides couldn't attack each other directly because of the atomic bombs, so they fought via proxies. https://en.wikipedia.org/wiki/Foreign_interventions_by_the_Soviet_Union
I'm sure there's a similar page about the states. The point is that neither side in the cold war was a good one. It was too bullies fighting for control.
I'm allergic to YouTube videos, so I'll rely on your text, instead.
I do believe it goes back to the Mongols where the Russian "ingenuity" was to embrace being slaves. They realised that at any moment the "guard" can come and take everything away.
Which means that stealing is not wrong.
And it also means that the best way of protecting yourself is by making the guard look at somebody else. Thus insatiable need for expansion.
Which is ironic since the guards left more than a millennium ago, but the system kept going.