I think the important part here was that the rest of the party was okay with the player being AFK for whatever reason. They could have been leeching, or they could have had to AFK for a legit reason-- you don't know that. I've had a situation where I've gone in with a group (with all of us on VOIP) and one person needed to temporarily AFK because their pizza was delivered. We all knew they would be back, so if someone had tried to kick them, we would've voted 'No.'

Heck, I once had to AFK right as a dungeon started because my parakeet got out of his cage. Fortunately I was with a group of friends, but things can and do happen and there isn't always a clear-cut way to tell whether an AFK is legit or not.