The above has very little to do with what music can or can not
communicate. It's not about what you thought the music communicated
but about your extra-musical associations based on, in this case,
false information or assumptions. You can really only explore that
field when you don't know what the music is supposed to be "about".
For instance, when I got to know Strauss' Don Quixote, I didn't know
the program. That was still more information than nothing since I knew
about the title character but I have never read the book. I think I
have seen a DQ movie a long time ago but if I did, I have forgotten
everything about it. I know about the windmills but hat's about it.
For some reason, I didn't read the program when I got to know the
piece, it somehow didn't interest me. In fact, even though I read it
at some point I have mostly forgotten what it is about in the
meantime. There are some obvious things in there like the sheep and
the chorale which IIRC signifies some wandering priests who DQ
attacks. But even that I don't remember that clearly. Yet when I
listen to the music, it communicates very strongly to me. I may not
know what the depicted adventures are but what is going on in the
musical adventures is completely clear to me.
Same about Till Eulenspiegel. I don't remember that program either
except that he is executed at the end. Then there are those pieces
which don't really have a program but which still convey vivid musical
images, like La Mer. what is the quiet middle section in the third
movement? Obviously, it is the becalmed sea. But is it at night or in
the middle of the day? I think it is at night, but I can't really
explain why. Nor do I know if that is what Debussy intended to
"communicate".