Lots of historical context here, all the way back to the Catherine the Great.
Its important to understand history if you're going to try to understand what is going on in the present. The history between Ukraine, Russia, Europe and more (including the US, given both World Wars and NATO) is quite-complex, and unfortunately many Americans seem to not know any of it.
This doesn't excuse anything, but understanding the complexities of the past help inform why things might have gone sideways as they did, and can serve as an important set of facts with which to view both current and, presumably, future events.