It seems to me that the same person who rants and screams at Mike and Lizzie because they follow network television's lead far too closely and fumes angrily at the irresponsible men in the mass media who aren't guiding her destiny for her in a way she approves of is something of a hypocrite. Since her mindset congealed into its current configuration when she was eight, it looks to me as if she shares Mike's belief that she's the protagonist of a sitcom.
This, it seems to me, would explain a lot of things about her failure to take heed of the world as it is. In the world of television, a child is simply a small adult who cannot read, write or use grammatical English and should thus be treated as an adult; the notion that this is not the case is not one Elly would willingly admit because acting as if they are what the guidebooks say they are take time her poor time management skills has robbed from her. It'd be like admitting that dogs aren't midgets in suits, that problems don't vanish in time for the Alka Seltzer ad, that bullies aren't losers who need to win and that war isn't a glorified game of freeze tag. We can even blame her disregard for her children's safety on her over-reliance on television as a guide to life. Not only do sitcom kids never come to real harm, Marian probably sent her out of the room when the Scare-em-straight ads came on to warn people to not get mangled.