The next generation will be in charge of running the world in just a few short years. What we expose them to right now will have an impact on what they choose as adults (including how they choose to take care of the older generation). For the long term health of our society, we need to hold children's potential heroes to high standards of moral behavior. That benefits everyone.
Just as there are professionals in educational or child services field that are held to extra high standards, people in entertainment should be held to higher standards. The initial cop out is usually freedom of speech and entertainment value, but the morals being taught to the children can be harmful.
It is my opinion that actors who act for child audiences should not be held to a higher standard than other actors because it falls to the parents of those children to determine whether the actor is an appropriate role model for their children. I feel that parents should more closely monitor who their children are looking up to.
I believe actors are performing a job and I do not think their personal life should be intertwined with their work life. These actors should be able to work in any facet they are hired for without regard to their personal life. Media has made these connections, not the employee or even the employer.
People who act in programs aimed at children are still just people. As long as they're acting decent on camera and not taking any inappropriate behavior onto their character on the television show, it shouldn't matter what they do off the set. People shouldn't be so interested in their lives off of the set.