Option for consistent mouse operations

Left click is also handling selection though. It would be very confusing if shift+click on an ally assisted them, and shift+right click added them to your selection.

Selecting a building in a menu is not a context sensitive action, or rather, it isn't what we mean when we say a contextual command. You're navigating through a menu, of course left click is select. It's not a contextual command

If you right click in word for instance, it brings up a contextual menu based on where you clicked, and what you clicked. You use left-click to navigate the menus.

Fairly new to the game, and finally understood the control scheme perfectly. Read through this thread and now confuses himself every time he has to do an action