For the PC, it is reversed since it's a console port:
You press the right mouse button to equip to the LEFT HAND.
You press the left mouse button to equip to the RIGHT HAND.
One of many PC flaws...
That's more to do with the fact that PC games traditionally use left click for your attack.
In Mount and Blade its left click to attack with your sword in your right hand, right click to block with your shield, is that because it's a console port?
Hell, even Gordon Freeman carries his crowbar in his right hand.