Juvenile uptight needy Mosquito

handle the stress of combat, or accept the consequences of going to combat. I mean, who joins up in the armed forces and thinks "man, i'll never go to war"?

You don't neccesarily go to wars to be considered serving in the army tho
And plenty people who have worked in the army didn't die.

Rosi makes the best point people forget- the army places you based in part on what sort of troops they need- but also based on skill and aptitude. There are TONS of non combat and non infantry jobs and a good portion of troops never see combat or even a combat area. But....

To the point raised about recruiting kids- an “old” football player is maybe early 30’s on average? You don’t just have the long term health liability- costs yes but also effectiveness and safety (hard to get blood pressure pills consistently to a combat zone or to a soldier cut off behind enemy lines for 2 weeks...) but infantry and many other jobs in the military are physical jobs. Lots of walking, running, standing long term, heavy lifting and hard labor. You may be deprived of sleep and food for long periods depending on conditions- and you may (especially in our last few wars) face extreme conditions like heat which any alone is taxing on the body- together they are EXTREMELY taxing.

So that’s matter of practicality 1 - younger bodies tend to be healthier, have more energy, and be able to cope with these stresses without... dropping dead like. 45 year old shoveling a snowy driveway or taking a jog on a hot day. Matter of practicality 2- it costs between $50-100k per recruit on average just to get through the most basic training to serve the “simplest” needs of the military. Skilled soldiers in other tasks can cost significantly more. So you want to get people who once you train them- you have the maximum chance of them returning that investment over the course of their career.