Obviously the loss of human life is terrible, but I want to add an economic reason also.

War is just absolutely terrible for the global economy. Munitions are single use. They explode and are gone. Not to mention the destruction of manufacturing, human lives, and general instability of wartorn regions.

Investing in infrastructure improves commerce. Investing in education, healthcare, and other social services increases worker productivity and number of workers. It's a no-brainer from an economic perspective to invest in all of those things.

A rising tide lifts all ships.