OK. What is music theory about? The explanation using frequencies, ratios, etc matched my understanding of the underlying physics and their effects on human perception.
It is mostly a descriptive theory in that it studies musical patterns (rhythm, melody, harmony, intervals, scales, modes, chords and chord progressions) but it can also be prescriptive (for e.g. - don't use certain note intervals in a guitar solo if you are using certain chords in your song)
None of this has anything to do with Physics. Music Theory is completely abstracted from the physical world.
See my other comment.
Similarly, it seems like studying the frequencies and their relationships illuminates at least a portion of what music theory covers.