Almost any diet plan that says 'Eat more of this and less of that' is going to cause problems for econpmically disadvantaged people. ER4YT is not unique in that respect. With enough money, you can afford to be highly selective in what you eat. However, while most people focus only on the things that ER4YT says you CAN'T eat, there is actually a much bigger list of things that you CAN eat. Focus on that longer list and select items that are readily available and affordable.
A lot gets said around here about organic meats and produce, and there's no doubt that there are additional advantages to those organic foods over the regular stuff. Thhat does not mean that you absolutely must buy organics, only that it is a bit better. For people with severe allergies or medical conditions they may even be a lot better; but most people don't fall in that category.
If organic red meat isn't affordable or available and you don't want to eat the regular stuff then focus on poultry and fish as the primary protein sources. Just watch out for the varieties of bottom feeding fish that often have high metal levels.
If organic fruits and veggies aren't affordable or available, then avoid the types that are known to be raised with the most pesticides; there's a 'dirty dozen' list (Andrew Weil's I think) that lists such fruits and veggies. I seem to recall strawberries and spinach as two of those items. If that is too restrictive, try the Clorox water soaking method that has been mentioned here on this site before to get contaminants off of the outside of the food.
On the subject of school cafeteria food, that's been a highly debated issue for decades. Regardless what the current wisdom is as to what is good to eat and what isn't, the kids won't get any nutrition at all if the only choices they're given is food they don't like and won't eat. If ER4YT is taken as the current wisdom, then you'd almost have to limit the food choices to only those that are neutral or beneficial for all four blood types. If not, the type A kids will be buying the red meat and the type Os will eat lots of wheat and dairy. They'll get tired of turkey, fish, broccoli, and rice in a big hurry.
There's no easy answer here, but educating as many people as possible about the subject is a prerequisite for getting any kind of consensus on a solution.