While I generally agree with your sentiment and there is likely a great deal of optimization still to come, the main menu is a rendered space. If the beta is like the playtests, you can very quickly switch to the soldier config screen with no loading. So while I suspect the GPU is "primed" even in that screen, I would agree that it should not be doing much rendering until you start seeing models and textures...
For example, Call of Duty, also renders soldiers and background but the PC usage is decent, not very high.
Also, when I alt+tab the game in menu, most of the rendering should be paused.
