Some interesting comments since I last looked at this thread yesterday.

Those who support the "US flag" argument seem to be trying to justify it based on Dylan's later persona and output. Like many a young rebel before him, he probably became part of the establishment later, and his musical output reflected that. (How much of a rebel is Mick Jagger or Rod Stewart these days?)

As I and others have said, the key to understanding the song's impact is to understand the political and social context of the time (early 1960s).

The "Freewheelin'" album (on which the song was issued) was the first Bob Dylan LP I bought (I didn't buy the 1st album until later, and I got all the others up to around 1970). That was my favourite album for the next few years and it's still my favourite Dylan album. But I have to admit the Blowin' In The Wind was never my favourite track, and to be frank, it was probably one of my least favourites on the album. When I started in folk clubs in the late 1960s a large part of my repertoire was Dylan songs, and I performed most songs off that album (even I Shall Be Free and Talking WW3 Blues!), but I don't recall singing Blowin' In The Wind much. I think even by the late 1960s, it had become a bit hackneyed and I was aware of that.