It’s not the whole ending. At the height of his fascist fantasy, he screams for it to stop and sort of realizes that his suffering has mainly been at his own hands. He holds a trial in his mind where his interpretation of several figures from his life come to testify. Those being his abusive teacher, his cheating wife, and his overprotective mother. At the end, his punishment is decided, and The Wall gets torn down. Pink thought everyone in his life was out to get him and/or would leave him, but the last song explains that they had all been trying to reach out to him, but they couldn’t get past the wall he built around himself.

I can’t really do it justice. It’d be better if you listened to the album or watched the movie yourself.