Someone very close to me suffers from ARFID. Imagine if you will that you were in the situations above. How long would it be before you tried eating dog poop? If people were telling you dog poop was safe and healthy and the only way to survive yet for your entire life you've known otherwise.

This isn't the greatest example, but that roughly gives you an idea of what someone with ARFID might be struggling with in those moments and why it is different than just picky eating.