All true & valid. But...
Going with what you say John O'L,this was also incorporated by Sam Cooke into his,slightly later, song "A Change Is Gonna Come"
This song was (IMO) more powerful & more precise than "Blowin' in the wind" & yet didn't seem to hook the public imagination to anything like the same degree. Was that in spite of its precision or because of it?
I recall one appreciation of "Blowin' in the wind" that concluded that the "answer" that was "Blowin' in the wind" was the stars and stripes.I think (possibly wrongly) that this is a misinterpretation but I feel that this is a song which lends itself to misinterpretation in a way that "A Change is Gonna Come" or The Internationale or,for that matter,"America,The Beautiful" do not.
Precision does not in itself prevent misinterpretation,here in the U.K. it is not uncommon to hear Christians or Conservatives sing "Imagine" though it is usually painfully obvious they are not thinking about what they are singing or why they are singing it.
"Blowin' in the Wind" would probably sound less anomolous,which is possibly why it mystifies me.