Ronnie Coleman did do cardio during his contest preps, but his cardio was always just low intensity steady state cardio on the treadmill. Nothing crazy. He would walk for 45 minutes 1-2 times per day while getting ready for his competitions.
Bodybuilders like Ronnie Coleman carry a tremendous amount of muscle mass. Their basal metabolic rate is through the roof to support the amount of muscle they carry. They don't need to do a lot of cardio because of that.
Most pro bodybuilders do very little cardio and when they do cardio, it's always low intensity. Watch any old Jay Cutler videos and you will see him walking on treadmill, using the step mill at low intensity.
Cardio simply burns calories. You don't need cardio to get in shape. You could just subtract calories from your daily diet to get the same effect.