In the modern world, nobody listens to a speech from start to finish. At best, the vast majority of people will get a handful of ten to fifteen second long clips from their favorite news and/or social media channel. So that's how modern speeches are written - they tend to be very short and are essentially just brief soundbites that have been stuck together in such a way to make it easy for other people to edit them down into clips.

Historical speeches were much longer - Hitler's speeches would often go on for >2 hours and that wasn't unusual among politicians that were good at giving speeches.

Historical speeches are often exhaustive explanations of what the speaker thinks is the problem, how they intend to solve the problem, and why other proposed solutions to the problem are inferior to theirs. While you can often pull brief snippets out of those speeches - such as "the only thing to fear is fear itself" - stuff like that often doesn't translate well from foreign languages.

Making sense of historical, foreign language speeches requires you to listen to the whole thing, which is probably several hours longer than the documentary you're watching.