How about point #4.
#4 Ukrainian government did it in order to make gain more hatred towards Russia from Ukrainian people and justify obligatory military drafts. They also did it because US-installed coup government feels that world is tired of them whining and begging for money, and by doing so they can once again say that Russia is an aggressor that declared war on Ukraine.
Given the dire situation in Ukraine, where people now earn less then poorest countries in Africa, the only drum they can beat on day in and day out has a label on it "It's because of Russia!"
"If anything can go wrong, it will." -- Edsel Murphy