Yup. People who consider the rear brake to be the main one, obviously ride on roads only. And likely on dry, even roads.

Where bicycle braking becomes interesting, is steep downhill, on low-traction surface. 80%+ of the braking force comes from the front brake, and it's a balancing act better suited to one's dominant hand.

I live in the EU, and it always annoyed me that they default the front brake to the left handle. It's an accident waiting to happen, on a mountain bike with hydraulic brakes and soft front suspension.