I feel ya on the motorist, but this is a compilation vid. The point of his channel/clips is to show how clueless pedestrians are and that they don't follow the law when it comes to street signs, which then makes driving all that more dangerous for everyone especially people on motorcycles. A couple of revs on the engine remind people that they are in a dangerous setting. Its sort of like making shitlord comments around people you love, just a subtle nudge of influence to ensure they don't get fat.