I agree that the myth is a horrid one and the thing that got it started was the practice of some new hobbyists doing 100% water changes in their tanks. In no way should the water changes exceed 50% during the cycle but they should be done for sure to control the amount of ammonia build up. It is different if you are doing a fishless cycle where the tank is not containing fish to be concerned with. Then they may be desirable but not absolutely necessary. But when there are fish in the tank assisting with the cycle the ammonia and nitrites and nitrates need to be controlled with water changes.