It's a little off-topic and a little cynical, but I think the larger issue here is that we've watered our teaching of history (and most things) down to soundbites and simple explanations. What we learned about Columbus, MLK, and all the founding fathers were stripped of everything controversial to create flawless heroes with views no PTA member would find offensive.
How many of the influential speeches in history have you read? I think Time's list is a good starting place. These were all inspiring, influential, and are all readily available for free:
If you have read even half of these, maybe then I'll buy the copyright argument.
Unfortunately, textbook are still a/the standard source of information in most public schools. Yes, this raises separate questions about the way that we structure our education system, but that's not the issue at hand.
The speech is readily found by those willing to go out of their way to look for it, but it is not included in most textbooks, because those publishers would then have to pay royalties to the King estate (and indirectly pass those costs along to the schools).
The video is much harder to find (legally, not illegally!), because the King estate controls it much more tightly.
Your points are still very valid, but something as significant as this should never have been copyright-able from day one.
Only one thing, is impossible for god: to find any sense in any copyright law on the planet. ~ Mark Twain
Eh, have you talked a teenager lately? I believe the standard source of information in public schools is a smartphone.
Exactly, or at least to neat narratives that are very much retrospectively constructed and do not really give a realistic picture of the messiness of how the events felt to those who were living through them. I think reading actual speeches, or documents written at the time gives a very complementary view to the neat narratives and insight into the value systems that people had at the time. Of course this is precisely the reason why reading them demands very much of the reader.
In general, I think, one should read more original works, and less later histories describing said works. It is more demanding, but also more satisfying.
Svante Myrick makes this point pretty succinctly in this video . He points out that all most people know about our history of slavery is "slavery, Abraham Lincoln, freedom". Or "blacks couldn't vote, MLK, blacks could vote". It's a ridiculously shallow comprehension of history.
"Inconsistent with the preferred simple narrative" is probably more accurate than "controversial" here.