You can assume its either lack of hygiene standards or hiding a weak chin for 90% of them.
Its also heavily dependent on climate. Where I'm from in the South all the hardest of manly men are clean shaven or mustached with beards being reserved for those aforementioned Lefties. But where I live now outside the Swamp beards are much more common in the working class and ranchers, with the Lefties going full clean or gay mustached.
You can assume its either lack of hygiene standards or hiding a weak chin for 90% of them.
Its also heavily dependent on climate. Where I'm from in the South all the hardest of manly men are clean shaven or mustached with beards being reserved for those aforementioned Lefties. But where I live now outside the Swamp beards are much more common in the working class and ranchers, with the Lefties going full clean or gay mustached.