Good vs. Bad Exercises
Very rarely can an exercise be described with a blanket statement as being good or bad. The real question is in what context is it good or bad?
Some seemingly bad exercises can be good in certain situations, and some good exercises can be bad under certain circumstances.
For example, I was taught as a child that stoves were bad because they were hot, and I could burn myself. But as I aged my parents also taught me that they were useful and could make life much easier when preparing food. So in one context, it's bad because you could hurt yourself. On the other hand, it is good because it can cook food.
It is no different with exercise. We must know what exercises do in order to decide what they are good for and what they are bad for.