I don't mind the absent parent theme to a certain extent, especially in a fantasy book. I think if it is a well crafted book..fine. If it is just a lazy hook for a TV show...not so much.
It bugs me more in TV shows....I think one of the reasons the show iCARLY bugs me. It bugs me less if it is a cartoon type show, where you might not see the parents but you assume they are there, as opposed to a real life type show. My kids are too old for Max and Ruby...but I have seen it a few times and so have they. I had mixed feelings...mostly liked it, but you'd think there would be times where the parents would intervene
There was a show on a few years ago...maybe on Disney channel, where it was a blended family and the parents seemed sort of checked out of the situation and the girl on the show had to deal with the challenges of having a stepbrother who was almost her same age and was a total jerk, with almost no intervention from the parents. I hated that show.