Raphael was the cannon leader in the movie.

Yes, you are right, in every other TMNT product, Leonardo is the leader.

But don't blame the song, blame the creators of the movie. This song is epic (way better the utter garbage that was Ninja Rap).

Side note: when I was in college, I went to a local band's concert (Estradasphere), where they did T-U-R-T-L-E Power live. My life peaked that day.