Yeah, IMO this isn't one of EGG's better takes.Gygax is crystal-clear in his PHB and DMG that XP are earned by the player as a reward for playing the game well. He also advises the GM not to manipulate the outcome of combats, because that would be contrary to the major precepts of the game. It's very clear that he has a conception of what it means to play well and be rewarded for that.
I've always seen xp, as much as possible, as being a reward for what the character (under direction of the player, of course) does in the fiction, rather than for anything the player does at the table.
This is why when I hear of DMs giving xp for bringing snacks to the game or for writing up the game log, I think "nope, not my cup o' tea".