Putina cannot let his own citizens can see how a very similar group of people are flourishing just across the border.
They were by no means flourishing.
Say what you want about illegal invasions, liberty, human rights, etc - but Ukraine had never been doing better than Russia economically. Not at any single point between today and 1991, did the Ukrainians grow faster than us, have higher incomes, or benefit from greater choice of consumer goods.
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The dangerous example the Ukrainians were setting, was that you could don kitchen pots on your head, and start throwing bricks at policemen and taking potshots at them from your hunting rifle.
The dangerous example they set, is that it is enough to bring 15,000 people from all over Ukraine to the central square of the capital - in order to topple a democratically elected government. This, while every single other city in Ukraine stays quiet, and most normal people continue trying to live their normal lives.
This is exactly what happened during the October Revolution, when a small group of fanatics enforced their will on Petrograd - and plunged the rest of the country into 80 years of misery.
What I don't understand, is why the West cheers for this and pretends it is democracy. Nobody in the West seems to be ok with protesters storming government buildings.
Nobody thinks the Gilets Jauns have the right to storm the Elysee Palace and throw Macron in a rubbish bin. Nobody thinks it's ok for Jan 6 protesters to storm the Capitol.
Nobody calls for the overthrow of Spanish government, when Spanish riot police fire rubber bullets or tear gas into crowds.
But in Ukraine they are angels. They are saints. Martyrs for freedom. Noble elves... Why? Because it looks and sounds like they are against Russia. That's it.
All that is required to metamorphose from an unemployed street thug into a George Washington is to announce that you fight "for freedom from the Russian yoke".