I'm actually surprised by this ruling. It does not send the message I think they intended.
Posmetukhov was allegedly angry with a captain who imposed disciplinary measures and threatened to transfer him to an assault unit, according to a document provided Mediazona.
Transfer to an assault unit is a near certain death sentence, so this russian killed that commander (and 3 others), and is now going to live for the rest of his life (in prison). This is sending the message to russian soldiers: "if you're in an assault unit, your path is to either live out a few more weeks on the front lines or to kill your commander and live out the rest of your days in prison".