I hated this scene the first time I saw the movie. Chaplin just completely dropped character and cold-stopped the narrative and the longer the sheer endless scene went on, the more annoyed I became. After all I didn't want to be lectured, I wanted to laugh. When it was over I was left confused and unsatisfied, because the story hadn't been resolved. It just had stopped.

I found that it gets better with repeated watching though. If you know that's the way the movie ends, you start looking forward to it and it actually makes sense. It's still filled with generalities and tries to tackle way too many issues at once. (What the fuck does the talk about machinery have to do with anything? That's what Modern Times was about.) But let's not forget that the world was on the brink of disaster at the time and the future was uncertain. The open-endedness of the story and the appeal to all of humanity to work for a better future fits that perfectly. And say about the speech what you want, Chaplin's delivery is sincere and that's what ultimately makes it effective.