You're not thinking demographically.... most of those channels are on at any given time during a day when you're a stay at home mom or a homemaker. (I speak from experience here.)
You could be cleaning house, doing laundry, taking a nap or whatever and still hear a new commercial for a STAIN REMOVER running in the background.
I don't know about you - but, as a mom, you cannot have too much stain remover in the house - especially if your kids are still young enough for things like diapers and jars of baby food and daily spills and stains.
I think the choice of channels is both cost effective and hitting a huge target audience - who does most of the shopping for a household - MOM DOES. Show her a product to make her life easier and, if it's readily available (come on NA), she'll remember to pick some up next time she's out shopping.
All IMHO