Great movie until the end

I thought this was a great movie. I thought it was well made, I loved Vincent Price in it, the script was pretty good, and for the most part, it was very faithful to Richard Matheson's novel I Am Legend. Matheson himself worked a little on the screenplay, but he was unhappy with the finished screenplay and took his name off. I loved the movie. That is, until the end. I thought it was stupid how they changed the ending. Matheson's ending to the novel was perfect. When I was watching the ending to this movie, I thought a lot of it was silly and I wondered what they thought they were doing.

The novel ends with a twist. Here he was hunting and killing the vampires and in the end he realizes it's futile because he was the only human left. He had become the monster. In the end before he dies, he sees them all looking at him and he laughs at the fact that they were all afraid. He says, "I am legend" before he dies. Rather than let them get him and publicly execute him, he takes poison and kills himself. This is the way the movie should have ended. Why did it have to end with them getting him? I thought it was stupid. I got so disgusted.