Yeah, I always used to get those two mixed up as a kid and I still slip up every now an again, my b. For me, what really floors me is that people would be interested in these stories without any additional narrative. Documentaries deal in occasionally mundane things, but so much time is spent trimming and editing that in the end all that's left is the artist's message. To a lesser degree I understand (and can enjoy) certain streamers/let's players because the main focus isn't the game. Yes, The Game Grumps, for example, play games but the main draw of the channel isn't the game playing, it's the banter, jokes, and story. Even combo videos make sense to me because it's a rush of the coolest possible things that could happen in a game strung together in a visually pleasing way to (albeit usually terribly cheesy) music. Blogs can tell a story, and that's great because it's not just a running camera into someone's life, it's snippets that the artist finds relevant to a story they're trying to tell.
Sportscasting, on the other hand, is just a running camera with a commentator explaining whats happening. They're often meant to be unbiased and give more informational context rather than telling a story. At this point, to me, it seems like there is literally no reason not to be playing the game yourself. It's simply not something I can get into nor can I understand how anyone else could get into it. I almost understand simply watching because you're passionate, but having an emotional attachment, such as a favorite player or team, is absolutely mind boggling to me.