Protection from indecent material

In the Sandvig article, I thought it was interesting that one of the three main areas the study looked at was indecent material and children. This article makes the point that this is a serious problem that has had a lot of focus --and in theory, it can be a problem. The results of the study raised some questions for me though. Obviously there have been efforts to pass policies to protect children but the children had no interest in such sites and quickly went on to something more interesting--like games. The article states, "...efforts have focused on restricting institutional modes of access to the Internet (i.e., schools and libraries), where parents may not be able to supervise children." Why are these policies getting such high attention by politicians in the first place? If parents are contacting their legislators, what is the motivation behind it? If parents are worried about what their children are doing away from home, are they worried about what their children are viewing at home? Wouldn't it be the same? Are parents just not monitoring their children while at home? I don't think this study is the first to show what children are most interested in doing on a computer, so I'm just curious why "attentive" parents can sit and at watch the latest news story at 10 about children and porn, and not already know about their own children.