Rdgrad, that sounds frustrating and I'm sorry you have to deal with older coworkers acting like you are less than.

If you yourself are disabled, have you ever heard of ableism? There are different types. Institutional, internalized, interpersonal. Its when "able bodied" people act in a way that sends a negative message to disabled people. Its like an unconscious prejudice. Its not okay, and you're not alone. There's a book I'd like to recommend, if you dont mind: Robot Check