Chess is different from other sports in that watching it "live" isn't really the best way to experience it. Half the time you'd be looking at a chess board with no one around it, and you don't get to spend time thinking where you want to think, you have to spend it where the players decided to. Lots of people are going to instead watch the game later, at their own pace, watching someone analysis of the game, or doing their own. It's not entirely unreasonable to not want that spoiled.