Anorexic vs Fat people

Why do people always try to protect anorexic people like they have some kind of mental illness but we don't do the same thing about fat people? If they're fat, it's because they eat too much obviously. But people call them pigs and they never blame on a mental illness.

Being anorexic, no one dares to cross the line and make fun of you cause it's an "illness". What if it's just the opposite of being fat? They just don't eat enough like fat people eat too much?

Fat people = no self control

Anorexia is more complex than that

Telling slim/skinny people to eat more: Considered nice advice and being helpful.
Telling chubby/overweight people to eat less: Considered insulting them.

Can't we all just be happy if someone is happy with their body? Like you can be kinda slim/chubby and still be healthy. It's another thing if you're more on the extreme ends of the spectrum but can't we all just fucking mind our own buisness and not tell others what they should do unless they ask for your opinion.