Context: in classical Greece, Sparta built a hegemony based on its military power that was formed around a core of professional hoplites, which was rare at the time as most military campaigns were fought by part time soldiers who were mainly farmers, handymen, etc.
This hegemony was broken when in Thebes the Sacred Band of Thebes was formed, consisting of 150 gay couples who became professional soldiers, too. These 300 (coincidence? Idk, but I find it funny) elite warriors were instrumental in two major defeats an outnumbered thebian army handed to Spartans who encountered another professional military for the first time.
The Sacred Band being made up of gay couples was intentional, as the idea behind it was that men would fight harder for and with other men they had a strong bond with and there was no stronger bond than love.
Idolizing spartan warrior culture is widespread among “alpha males” and the manosphere. Another funny irony that followers and propagators of such a homophobic idiology idolize a culture that was defeated by an explicitly gay warrior unit.
It is interesting to think that societies would not only (forcibly) include specialized individuals necessary for civilization in frontline combat but also provide them with little training, equipment, or screening for aptitude. If i were to set aside my own opinions about war and forcing people to participate in it, it would simply be wiser to not only have a specialized class of soldiers, but to also eliminate individuals not suited to the task. Militaries into the modern era also have the issue through nepotism in the officer corps and incentivising the most impoverished to join the enlisted, they have the benefit of significantly larger numbers (total population), mechinization, and long range engagement. Even the most catastrophic combat in the modern era does not have the same (immediate) death toll.