Many children and teenagers do watch the debates and speeches and view many other things having to do with the election. As brought up in the last debate someone asked as candidates if they thought they were being appropriate and or making a good impression on the younger audience watching for school purposes. I don't quite think either of the completely answered the question but overall I think they both know they are not.
Especially, as shown in this commercial the way Trump has imitated disabled people, sexually assaulted woman, and has mostly talked about himself that he really has no filter on what he does ans puts out into society. He is clearly a bad role model for the children of america. No child wants to grow up in a country with a president like that. I think that is why this advertisement is strong on Hillary's part.