Nobody stole anything. He sent out an unmarked script to actors, and they gave it to their agents. And since nothing on the script said "don't give it away" the agents gave it away, becuase that's what they do. It's normal business. Tarantino is throwing one of his temper tantrums.
I don't support the status quo. I support holding sleazy agents up to the light for public inspection. Good for Tarantino for holding people responsible and accountable.