After mulling it over, I have to say I think schools should serve healthy foods even if it's not appealing to the children. As someone said in the other thread, if they're hungry, they'll eat it. It shouldn't be school's responsibility to make sure someone's children reaches their caloric needs for the day. And, yes, it's sad that children of single parents working two jobs might go without, but that's not the school's fault. If anything, I think the idea that school/society will take care of the kids only facilitates bad behavior. Not that having consequences will eliminate single parenthood entirely but maybe it will give more people pause not wanting to bring children into the world when they can't provide for them themselves. Or, as the child, using that experience and not wanting the same life for their own children.
*Edit: Or, if it is the school's responsibility to feed kids, go all in. Send a note to parents that the kid's caloric needs are met for the day and, aside from a granola bar or two (heck, even send the kids home with those), don't need any additional food from home. That saves the parent's time and feeds the kids. That said, all kids grow differently, so I don't think having the school in charge is a good idea. But, hey, someone has to take some responsibility somewhere. Whether it's the parents or the school I guess at the end of the day I don't really care.