Did you forget how as soon as the war started, the Russians protested and thousands were arrested, beaten, jailed, etc?
The people in Russia have family and children to worry about, you can't blame them for staying and not wanting to risk starving and leaving with nothing.
Not to mention that they know their country is in the wrong, so they would also be fearing oppression outside of their country as well, not to mention losing all of their assets, being homeless, potentially starving.
The people that will be fleeing now will be desperate. It's clear that all the risks they face outside of Russia are now less than what they face remaining.
The citizens of Ukraine have had it incomprehensibly worse obviously, but that doesn't diminish the plight of Russian refugees now, it all adds together in the cost to humanity.