I understand what you're saying but my take is that it's really no different than when you're at a friends house and you're taking turns on the new single player game you just rented (I mean, if it was 2006), except the only downside is it's never really your turn to play, but you're enjoying your buddy make jokes while you play.
Sports (and by extension, e-sports) are in a different category for me. Watching someone let's play a game is more akin to watching a hobbyist fishing show. It's entertainment if you like fishing because it reminds you of fishing (this is a bad metaphor, abort)