I am also unhappy about this. It’s fine for online game play to be restricted to 16:9. However single player and non-ranked should support 21:9. All menus should support 21:9.
Also STRETCHING the game to 21:9 is not acceptable. It needs black bars on the sides so the content looks normal.
Additionally in my case I do not have any options above 1920x1200. I can’t even choose 2560x1440.