It is not good thought.

Good thought so directed would be helpful, useful, beneficial.

This is injurious, harmful, baneful.

Evil thought, worry, directs to the person, or to that part of the body considered, an injurious and baneful influence that produces pain, inharmony, unhappiness.

It is as if one were to divert a stream of corroding acid upon a sensitive wound, and do it because we wished to heal the wound.