Why does WIC no longer give vouchers for soy milk?

A friend of mine has a 2 year-old that is allergic to dairy, but she is on WIC and they no longer will give vouchers for soy milk or cheese. With all of the kids that are now allergic to dairy why would they choose to take that away? The mom is disabled, as are both of her kids so she can't work. Soy products are expensive and puts a big dent in her food budget.