Sorry Wookiecookie, big fan here, but you're wrong.
I agree this guy was being a jerk for the sake of being a jerk, but in the context of the actual offense committed, a time ban was overkill. A simple warning should have been the first step, and then a time ban if this guy really is abusing the client to annoy him teammates in a way they cannot stop him.
However, I think a better solution, overall, to prevent what is a silly case being in the Tribunal, Riot should look to tweaking their game client. If players could disable hearing emotes, then emote spamming can't be considered unavoidable harassment.