If you look at any profession, the majority of people are good. They do their jobs professionally day in and day out. They serve as examples to their peers and to young people who yearn to join their profession.
Then you have the bad people. Those whose actions are oftentimes highlighted in the press and give a negative stigma to the profession as a whole.
An current example would be those few police officers whose egregious actions have shed a negative light on law enforcement as a whole.