“Ukraine refused to abide by terms of its separation from Russia”
Read that again. That Ukrainian sovereignty from was “conditional”, ie, those things that make a nation sovereign, like ability to defend itself, to ally itself with friends, are reasons to revoke that sovereignty.
The war in the east has been fuelled by Russia for years. It’s escalation from a separatist movement to a war is due to Russian interference from the start. Likely a long term plan for what we are seeing today. One thing the Russian invasion of Ukraine has done is to shine light on Putin’s ambitions and long term plan to “re-sovietize” Eastern Europe.
Nothing justifies Putin’s actions in Ukraine. He is a power hungry bully. He cares for nothing but his own power, enrichment and what he sees as his “birthright” to rule Russia (and whatever other countries he can “re conquer” till he dies.