I doubt they will do a movie about that woman, but then I imagine it would be pretty boring.
And the decision to kill Swank was her own choice not Clint's choice. He wanted (needed) her to live because she filled a void in his life. But that isn't what she wanted and love does involve putting someone elses needs above your own. And there are other things in real life that can be done before the choice they made is made, but in a movie time constraints exist. And I doubt most people in her situation bite their own tongue off in an attempt to bleed out, and have to be drugged in order to keep them from killing themselves. In that situation (her situation) death was the best answer. But the film doesn't say it is the best or right answer for everyone.
You're right, it doesn't. What is does is dramatize this instance as the best choice for this character. Hollywood makes your heart bleed for her (read your post) you know in your heart that the Eastwood character did the right thing.
The whole movie begs the question, why did Hollywood produce it? What was the point? An artistic work about what? What are they trying to say? Why did the producers pick this story?