It is actually ergonomics when it comes to helicopters. It has nothing to do with torque. Helicopters turn left or right just as well. They don’t care. But you are correct with the Bell 47. It is due to the seating. Same as the MD500.

You can’t let go of the cyclic for long when flying but you can let go of the collective for a good period of time. So for frequency changes or switch operations, the left hand is normally used as that is the hand on the collective. So it makes sense that the instrument panel/radio stack is mostly to the left of the pilot. Which means the pilot is on the right.

If you’re doing longline sling work, you’ll find that the pilot will usually sit on the left if possible, as it is much easier to lean out over the collective to see the load under the helicopter, than to lean away from the collective. It stretches your left arm a bit if you lean away and makes it a bit more difficult to fly.

Helicopter pilots ALWAYS fly right hand on cyclic, left hand on collective. That is how all modern helicopters are arranged. Fixed wing is not like that. On the left seat of a Cessna/Piper, you fly left hand on the yoke, right hand on the throttle. If you’re in the right seat, you fly right hand on the yoke, left hand on the throttle.

So fixed wing are the odd ones out. There is no good reason for the captain to sit on the left.