I agree with most of that, except: "If you're fat, don't be fat. It's easy."
Logic would show that if people hate being fat, and not being fat is easy, then no one would be fat. As that's not the case, something in your argument is wrong. Hint, it's the "not being fat is easy" part.
There are several reasons why not being fat can be hard. For one, genetics. For another, upbringing. And, particularly in the West, eating a healthy diet can be difficult when we're constantly being sold lumps of sugar and salt disguised as actual food.
Unlike drugs, alcohol, smoking, gambling and other addictions, an eating disorder is not something you can quit cold turkey, as we all need to eat. Imagine if you had a drug addiction, and weren't able to remove that drug from your life, but had to instead give yourself a small taste of it every day. That's not a very effective way of overcoming an addiction!