Yes, there are some people who do have a genuine medical reason for not removing their shoes. We must make exceptions for them.
Some people say having a shoes-off policy causes embarassment for such people because they must reveal their condition. However, this is quite unnecessary. A person with a medical condition can simply say:
I am sorry, I can't take my shoes off. Doctor's orders.
She does not need to reveal the nature of her condition. She does not need to give any embarassing details. There is really no problem here.