It's like a car wreck...
I've heard this said, and it's really true: This show is like a car wreck: it's horrible to watch, but you can't look away.
I, personally, love it. It's probably a "guilty pleasure", but I haven't missed an episode yet.
No one makes these people come on the show. They try out, they take the polygraph, and they come out and sit down, knowing the questions they were asked, and knowing that 21 of those questions are going to be asked on national television. I'm not saying it's a good or smart thing to do, but it's their choice.
I think most people like this show for the same reason they like to gossip: it's fun to know these little, embarrassing details of a person's life. Watching the show, in my opinion, is harmless. Watching it is not going to want to make kids lie. However, due to the sexual nature of a good part of the questions, I wouldn't say this show is for kids.