Agreed, in fact I'm not sure I've seen any really good studies of the negative affects of computer usage on kids, other than the obvious affect of not being active at that time.
Screentime close to bedtime and having a computer in a child's room have been found to negatively affect sleep.
I do give my kids to some screen media in part to give them social capital. They were much more limited as young toddlers. I really think there is too much crucial brain growth happening at 0-3 to spend vast chunks of time in front of a screen. It may not be so bad, but we have very little data.
We have had screen media feel in and out of balance here. We had a game that really obsessed the kids for a while, and they pestered us a lot about playing it. I think they would have played 2+ hours a day if allowed (the game really is addictive, even for adults). Not cool with me. OTOH, they are not very interested in TV at all.
