To reduce complex issues, such as the causes of the reduction of real wages over the last 25 years, cannot be reduced to a 20 second sound bite. They tend to distort reality. In any endeavor, government included, we should be searching for truth.
Any deception is therefore evil and harmful.
They are used to distort the real issues Democracy entails free choice. It is their choice to try and influence the voter. It is the voters choice to let the influence bias their educated opinion. Commercials are not long enough to focus on issues with substance. It makes people look at the candidate's appeal and appearance rather than focus on the issues.