There's a big difference between submitting something you've made beforehand versus submitting something that was made during the actual jam, or perhaps even better made for multiple jams that happened to be at the same time. While his code repository history isn't the most informative, that along with the fact that it says "... Edit: Seems like the post was cut here for some reason. I just wanted to point out that the repo and the game page have the same dates for when they became available.
I understand being frustrated about someone cheating in a honor based event like a game jam, but false accusations aren't much fun either.