What Finn did was horrible and inexcusable, no question. In the real world. But the world of the 100 is a world of barbarism. And even in that world, everyone is forgetting the horrible and inexcusable terror perpetrated by the Grounders prior to the incident at the bridge in season one, outside of the theater of war. They murdered sky teenagers, who had not intentionally caused any harm. They used horrifying biological warfare to "soften" the battlefield, causing both atrocious pain and death. Both sky people and grounders have committed barbaric acts without real consequence. Look at Murphy. I'm not saying Finn did not deserve punishment, but the spectacle of it all is insane given everything everyone has done "in order to survive."
Review of Spacewalker
