Why is the fundamental attribution error considered an error?

fundamental attribution error is considered an error because of the fundamental attribution error, we tend to believe that others do bad things because they are bad people. We're inclined to ignore situational factors that might have played a role.

Explanation:

The fundamental attribution error is our tendency to explain someone's behavior based on internal factors, such as personality or disposition, and to underestimate the influence that external factors, such as situational influences, have on another person's behavior.

So, the fundamental attribution error explains why we often judge others harshly while letting ourselves off the hook at the same time by rationalizing our own unethical behavior.