I'm not saying the guy belongs in jail or anything, but "ill intent" seems exactly what he was going for, although mostly for curiosity's sake, not for any real gain.
FWIW, plenty of people have gone to jail for price fixing who never intended to "ruin the entire market". I'm pretty sure most would fall into that catagory. They usually don't want to ruin anything, or even do anything detectable, they just want to make a mint off of whatever they can manipulate.
Scale is everything.