A manufacturer of toy planes who test flies one before sale, is doing it commercially.
A retailer of rubber band powered balsa gliders who flies a demo inside his store is flying it doing it commercially.
A kid's video of his Xmas present balsa glider flying past the Xmas tree, and posted on YouTube with ads is commercial flying.
Strict interpretation of the FAA's words lead to horrible absurdities.
Horribles are what lawyers use to get laws stricken down by courts.
People who write regulations need to temper zeal with reason.