My 2 cents:
This is punishable.
Reason 1: This is an ARAM game. ARAMs are normally a bit more care free and less serious than ranked or normal games. Someone spamming audio all game can be annoying (trust me, see below) and since everyone is in all chat, and people were asking to stop, and you didn't, you were ruining their gaming experience. Violation of Summoner Code, punish warranted.
Reason 2: Had this been ranked or normal, I would have a different opinion. I often times will (not spam mind you) use the taunts/laughs/jokes to rattle my opponents. Especially with my main, Lux... dat /laugh... Not only can it cause stress and annoy my lane opponents, but you can also take pressure off of other lanes: Say your top is getting double teamed by their top and jungler. If you're in mid with Lux, let's say, and you're spamming /laugh after every damage or kill... I guarantee you... the jungler will start coming mid more often, or mid will become more aggressive and make mistakes. It's a viable tactic and there isn't anything in the summoner code strictly saying "do not spam things we put in the game".
Keep old thread closed. Close this one. Punishment warranted. Tribunal working as intended. /thread