They refuse to acknowledge it because they haven’t experienced it themselves and, by that very fact, are demonstrating a complete lack of empathy or false empathy. This is an extremely exclusionary viewpoint is destructive and willfully ignorant.
I have multiple diseases ( all invisible) and I am overweight. I see it in their faces: people look at me and think “lazy”. They don’t ponder my plight; wonder if something hurts or if my fatigue is unbearable. And I guess I don’t expect them to.
It comes to a point where people start making you doubt your own body.
Here are examples of why it’s important to trust your own body and to push the medical professional to take you seriously.