That is because you see Putin in the context of Putin. But he, a KGB officer, should be viewed in the context of all the crimes of Communism: the Red Terror, the Golodomor, the liquidation of the kulaks, the collectivization of the farmers, the bare-hands industrialization, the endless foreign aggressions in the 30's, the export of Communism to Central Europe and Asia, etc. Plenty of material to find human sacrifices on a much larger scale than that.
Putin’s not a Marxist-Leninist anymore. All he really believes in is power. As a ex-KGB, he’s certainly capable of ruthlessness. Also, as I said, there’s no real proof, so far. I prefer to wait until something more concrete comes up.