In my most recent haircut (new salon for me), the lady cut my short hair over my ears as requested, then blow-dried it forward and proudly announced “See it hides your hearing aid!”
Why did she assume I wanted it hidden?
She was being kind and very thoughtful, in her mind’s eye.
To me it was a form of discrimination via kindness. I graciously smiled and said I liked the haircut. I did like the haircut, but never ever have I cared if my hearing aid showed.
Strange.
Let the River Run 
Sorry that happened to you. I guess cutting your hair the hearing aid was so visible to her that she thought it should be hidden. She probably thinks that what she would do if she were wearing a hearing aid.
Sad but true: she like so many others have been conditioned to think that a disability is somethng to cover up. Why should it be covered up? And who’s to say what a disability really is?
There are people with messed up attitudes who could pass for being “disabled” but would never be patronised for it, innocently or otherwise.
Hopefully one day people will learn not to discriminate.