> public seldom sees more than snippets of one of the most highly regarded speeches in history

Are you saying none of these is the full speech? Some are even explicitly labeled as such.

https://www.youtube.com/results?search_query=martin+luther+k...

The full text of the speech also is widely available, including via the National Archives in the U.S.:

https://www.archives.gov/files/press/exhibits/dream-speech.p...