I've felt the same way sometimes. Barb, I can totally relate with ending up feeling like I need to make the offending person feel better.
Finally, I just got tired of trying to make insensitive people feel better about the way they act and quit trying to answer them in a way that would excuse their inconsideration.
It took some trying but I finally am at the point of feeling like I don't owe anyone an explanation of why I do anything. I'm not rude (my Mom would turn over in her grave if I were) but just truthful.
I figure if they're brave enough to ask a total stranger why they feel the need to carry a cane they can handle the truthful answer I choose to give them!