It's kind of a self-sustaining problem. Russia has conscription for men. 99% of the guys I know (me included) hate this very idea and did their best to not serve (there's an entire underground industry dedicated to military service evasion). The remaining 1% did serve in the army, and consider it to be the worst year of their lives. So, as you imagine, most people that do end up in the army are generally the ones that aren't very smart and/or don't have the resources to evade it. Which you can pretty clearly see from their behavior in Kyiv oblast.

It's kind of a negative selection that's been going on for quite some time. Conveniently, Maxim Katz's yesterday's video is about negative selection but higher up in the government: https://www.youtube.com/watch?v=J4kmwnZ4l_s