You cannot use your wiimote to select the menu items, you can only use the controller's D-pad. It's how Smash games have always been. Plus, there is really no reason for you to use touch screen controls for the game.
Also, when one of the primary distinguishing features of a product is a touch screen enabled device, in my opinion you always have a reason to allow use of that screen for controls in game.
For the fighting, sure, but there's no reason that Nintendo's touchscreen tablet console shouldn't have touch controls for the menu.
Perhaps a better example is the T9-like keyboard you use to input player names in Smash 4. You're playing with the Wii U Gamepad, a touchscreen tablet that's the main differentiator of the console, and you're selecting T9 letters with your analog stick like you're using a Nokia phone in 1998. Why is there no on-tablet keyboard?!?