Myth? It's a well-documented Russian tactic. They basically have a two-tier military at this point: competent professionals, and untrained expendable cannon fodder. Professionals are used to operate weaponry that's more sophisticated than your basic AK, machine gun and 70s-era armour. They are valuable because of their training and (at this point) a lot of experience. The second tier is used to conduct the kind of attritional warfare that requires far less training of individual soldiers or smaller-size units, and results in very high casualties. This type of offensive operation makes slow progress, the only real downside being the sky-high casualties, so recruitment and training adapted - take everyone regardless of health and age, and give them just enough training to accomplish something before dying. It's very effective if you don't care about the lives of these soldiers. The professional tier goes in to exploit a breach, mans the self-propelled artillery, flies the drones, etc.
I think everybody is confusing the means and the ends, when it comes to these wars. They are not sacrificing people as cannon fodder because they are desperate to win the wars, instead the wars are the excuse for the real purpose, which is to have people killed. A sacrifice to demonic entities, whether they are imagined or not. The literal creation of hell on earth – that is not imagined.
The Aztecs and other ancient people like the Vikings didn't make excuses, they made war for it's own sake to please the entities they were worshipping with the blood of men.
This dates back to WW2. The "special echelon" made up of penal units (i.e. former convicts and soldiers being punished), the only difference is that during WW2 you were excused from the penal units if you were wounded (and happened to survived).
And of course it wouldn't work if the commanders didn't have informal authority to put their soldiers into pits or summarily execute them - also well documented.
