Why? Because --oops, silly me-- I didn't do my research in advance! These heights should be more accurate from now on. If you look at the old ones... just imagine Javert's slouching. A lot.
Honestly, I blame the camera angles in the Dream Cast. It's nearly impossible to get a real good estimate of peoples' heights...
Poor Jareth. He's the only normal height one.
Erik belongs to Leroux and Webber.
Jareth belongs to Henson, Lucas, and Bowie.
Norrington belongs to Disney and Bruckheimer
Javert belongs to Hugo, Boublil, Schonberg, and Kretzmer.
Pirates of Penzance belongs Gilbert and Sullivan.