My 40 Foot Class A after a long sweeping right turn and an immediate left turn at 20 mph almost rolled over. I've made many left turns at a greater speed without that reaction.
With the exception of Executive's out of line comment, I fail to see any others that may have ruffled your feathers. For his comment, I apologize, but the rest are just trying to tell you that mh's just aren't built to take this kind of treatment. Slow is the name of the game with them.