On the theme of the article, sound is a great way to understand what is going on, and I really like how you've used it here. I think some people believe that hearing mainly applies to obvious sounds such as speech and music, but it is, as you demonstrate here, an excellent diagnostic tool. I've personally learned that all of the little sounds contribute significantly to ones mental map / model of the world to the extent that I'm prepared to believe that total deafness would be as devastating, in the long term, as total sight loss.
just keep rubbing it in
I don't usually agree with the pro-social-justice, everything-is-offensive PC crowd. But sometimes, a joke is in bad taste. It's not the end of the world, it's not a horrible joke the author should be ashamed of, it's not a huge deal, and "sorry, you're right, fixing" is a perfect response.
Your response however is full of severe insecurity. "Grow a backbone", as they say.
How can you tell? Why not give the benefit of the doubt that the apology was sincere and not grovelling?