You escalated a situation and made it worse.
The issue is simply this: You responding the way you did is more egregious than what was done to you. Nobody cares “Who started it…” unless the person who started it was really insulting and out of line.
Have you ever heard of the term/concept of “de-escalation?” You did the opposite: You clearly escalated things in a very aggressive and demeaning manner. Especially when you said this:
“Shove your idiotic snobbishness about music, of all things, where the sun doesn't shine.”
That’s beyond the pale and uncalled for. If I reacted this way to every person who disagreed with me about my music and media collection habits, I would have no friends.
For example, I once told an audio engineer friend of mine that I rip to VBR MP3s, he gasped and explained:
“Storage is cheap… Why not just use FLAC for everything?”
I explained I am on macOS and want to have as much space saved on my iOS devices as possible and at as high quality as I can deal with. He went on and on ranting about macOS, uncompressed audio and this and that and the other…
You know what my response was? It was simply:
“Look you are an audio engineer; I am not. And if I have more music in my collection than I can remember, I find that to be a distraction and not a benefit. And the quality difference between FLAC and MP3 is something I really can’t notice — and honestly don’t care about — for the most part.”
I literally said that.
And that’s it! And that’s in the real world.
Yes, the original poster sounded snooty… But who cares? There is no such thing as a “best” way to manage media. Each person has their own method.
In your case I would have recommended not responding, flagging the comment as irrelevant/“no longer needed” and move on.
If you somehow need to say something just say something like:
“This question is about my specific issues; not a critique of how I am doing things. I’m sorry you find this appalling, but it’s not something I am concerned about.”
Or maybe — better yet — just don’t say anything. Who cares? Before MP3s existed there have always been music and media format snobs. Ignore them; they will never change.