It's simple really. Atheists aren't worried about being converted. If someone with proof of god shows up, we'll believe. But theists believe because of faith, and they are very worried about losing it. Reason, or even a good atheist who doesn't kill babies might threaten their faith. So they silence you.
If there is a god, I want to believe that there is a god. If there is not a god, I want to believe that there is no god.