I've seen Coleman he can't be a centimeter over 5'10" at the very most. But, until you stand next to him, he tends to give off the illusion that he is about 7'2".
Proportion is the name of the game, as was mentioned. On average, taller people (6'1" and over) tend to not be as proportioned as guys under 5'10", guys under 5'6" tend to look like midgets (no offense to anyone) and they get no love from the judges when standing next to guys between 5'9-5'11", ever see how ridiculous Lee Priest and Shawn Ray look next to the rest of the lineup, which is why neither one of them will ever be Mr. O, even though Ray deserved it 2 or 3 times at least. Franco Columbo won it despite his height because he was Arnold's boy, and nobody will argue that. I think he should have remained in powerlifting, cause he was one strong motherfucker, but he sure as shit never had the best physique in all the world.
All that being said, I think the idela height is between 5'7" at the absolute shortest to 5'11" at the absolute highest. There are of course exceptions like Gunter, Quincy Tailor, Ferrigno, but on average the taller guys don't have the proportionate physique and tend to always look like they have an imbalance somewhere.
Way back when, I think guys looked better at 6'1" or so with a wasp waist and barn door shoulders, but nowadays you needs freaky thickness throughout the legs , and longer limbed BB's seem to have a harder time with that.