I haven't read the articles yet, but I wanted to give my experience. When my son was 3 months old my husband was layed off and subsequently I had to go apply for WIC for some of our basic needs, one of which was not formula. I told the lady that my son was 100% BF and she said "well, we will just give you the formula anyways, in case you change your mind." Yes, I was outraged and felt like I was being sabotaged. I quickly told her that no, I would not be interested in the formula checks and she just kinda shrugged and went ahead with the other things.
So yeah, I can definately see how WIC could be the number one purchaser of formula.