I was surprised to see a post by Petzold on this subject. I know who he is. But I don’t think you owe an apology here. I think you made a thoughtful comment. A post like his should be critiqued for what it says, not for the author’s previous work. And, fortunately, other people could give context on the significant work he has done.
I'm familiar with the subject matter. I'm not familiar with the author.
I love classical music. I've been singing in a choir since I was 7, playing the piano since the same age, and compose music myself (https://youtu.be/7Tex-OUk6ZM). I’m actually on my way to church right now to sing some Howells.
I use Spotify every day
I use AI every day
I have enough familiarity with the subject to have an opinion and express it. I'm sorry that I haven't read the author's book.
I love classical music, and I am convinced that 90% of the reason people think they don't is because of people like the Charles Petzold. Deriving your self worth from being an enjoyer of art that someone else created is the high pretention.