This definitely looks like an SMW romhack, so why isn't it labelled as such?

This rom hack was submitted to speedrun.com before SMW Rom Hacks were accepted by series moderators. This is why this hack is not under the "SMW Rom Hack Series". You can find a few other hacks under the same situation. It isn't really an issue, it doesn't affect the leaderboard at all. It is just a byproduct of previous submission rules.