Underwear offers a barrier that keeps residual urine and feces particals from absorbing directly into your pants.
People that dont wear underwear let their bodily fluids make direct contact with their pants, and then expose them directly to any surfaces their bits might touch.
Not wearing underwear is unhygienic.
I agree with you and all the other commenters who have this same perspective. I’ve spent decades mostly commando. However recently I decided underwear is probably a good idea because some of my pants have been chafing my tender bits.