I'd like to raise this issue again. Most games don't have a rating button on mobile, even though they can be rated otherwise. It's hidden by the Comments button as shown in the above post (and the other buttons - it might be visible if the author has only one game and so the button to go to their profile doesn't show up, for example). I circumvent it by using the PC site on mobile, but it's inconvenient and seems like a relatively easy GUI fix.