Why do we teach the orthodox stance?

All of the above lol Pretty simple really, balance, best use of your best hand and agility. Having said that, I've seen a lot of kids, when they're young, be pretty ambidextrous in boxing and then as they get older, they find a stance that suits them better. Naturally, orth for right handers, south for lefties. Its just how it works.

I used to switch fight, when I wanna box my opponent I would go orthodox, use my left hand and stay on the back foot, if I wanna brawl I go southpaw so I can land the right hook and the left uppercut

Balance and coordination plays a key role. I'm a natural rights but I fight southpaw

After analysis the stance is determined by the best balance achieved in movement and punching accordingly. Comfort and center gravity and flexibility also. Not much to do with the power from the back hand. Most kids are better suited with their leverage hand behind the lead. Ray

Yep AK just answered it. Why would you want to be just jabbing with your strongest hand?

It's whatever hand you hit harder with a strait.