When you kill a chicken, Mrzzy, it causes unnecessary pain to the chicken. This is bad from the chicken's point of view...good from the point of view of the person who intends to eat the chicken.

Hamlet was correct, because he stepped back and saw the larger picture, rather than just seeing it from his own angle. This would not prevent Hamlet from feeling that it was bad when his uncle plotted the murder of his father. It was "bad" from Hamlet's point of view, and Hamlet's father's point of view. It was "good" from the uncle's point of view, because it allowed him to become the king.

Most people would have thought of it as "bad", because it was murder...but the few who stood to gain directly would have reasoned it as "good", because it was good for them.

To bomb a city is "bad" from the point of view of that city's population...but it's "good" from the point of view of the military high command on the opposing side in a war.

There are a million other examples.

To be able to see what Hamlet saw is not to justify all harmful actions. It is to recognize that some people will always see a specific harmful action as "good", because they derive a benefit from it. This indicates that our notions of "good" and "bad" are, to a large extent, subjective....although there are certain general types of actions that most of us will agree are "bad"...thus we work out various moral codes to deal with it.

Even Hamlet's statement can be seen as "good" or "bad" depending on how you look at it. ;-)

It's easy to assess an action as to whether it's harmful or not. If it damages, it's harmful. To slaughter the chicken, for example, is unquestionably harmful to the chicken! It dies. But is the action "bad" or "good"????? Well, that depends on the viewpoint of the one making the judgement. Some people feel it's "bad" to kill any animal for any purpose at all, including for food. Most don't think that. Whether it is "bad" or not is strictly a matter of opinion....but there's no question that it is harmful to the animal in question.

Human construction and agricultural are harmful to a vast number of plant and animal species, as they are deprived of habitat by those human activities. But is human construction and agriculture "bad"? Well, that's a matter of individual perspective again. To humans, it's "good"....unless they are people fighting to preserve the natural habitat.