Earlier quoted context omitted.
> The Soviets had blocking battalions ordered to shoot any of their own comrades who did not advance. Well, yes, but also not that straightforward. https://www.reddit.com/r/badhistory/comments/3igu17/on_the_c...
The fact they existed at all makes the point that the army discipline was forcibly applied, including executions for cowardice. Even just a few executions gets the point across to the troops.
And that's one example, from one particular culture.
Executions for desertion are very rare in western culture armies. Not that western culture armies couldn't be cruel. Field Punishment No. 1 is culturally engrained in my country: https://nzhistory.govt.nz/media/photo/field-punishment-no-1
That said, you seem to be implying that all armies ever have relied on force to recruit and retain members, which rings hollow.
If simply because my step-father, an Englishman touring the world, happily volunteered to fight the North Vietnamese as part of the RNZA, as did many others, all of NZ's troops in that war were volunteers. No conscription at the barrel of a gun.
Hell, during WW1 and WW2, people were faking their age to join up.
Reality is a lot more nuanced than you're making out.
I mean, we're social animals, for millennia we've lived or died by the group.