Sorry if I sound like a bit of an idiot here, but I've tried following this game on both Microsoft Edge and Google Chrome but the button is completely unresponsive. Is there a limit on what games you can follow, or are you not allowed to follow it for some reason? Is there another way I can add it to my followed games? Thanks.

Someone can correct me if I'm wrong here but I believe you can now only follow up to 100 games. Since you're currently following more than that you'll need to unfollow a few to be able to follow any other games.

Probably to not overload the site. Following too many games might send too many packets at once and crash the site.