But!! Twitter only lets you do this one person at a time. Going to everyone you follow's Twitter profile and clicking "turn off retweets" for each one of them takes FOREVER.So this app helps you do it more quickly! It's very simple, it just uses the Twitter API.
To get started, click "Sign in with Twitter!".
I don't like it either. The reason you need to give it permission to post tweets is that Twitter only has 2 levels of permission apps can get: "read-only" and "read and write". So because this site needs to do writes (to turn off retweets), it also needs permission to do every other write action, like posting tweets.
You can revoke access in your Twitter application settings when you're done with it.
This app will never post tweets for you. You can read the source. The only thing it will ever do is turn off retweets for some of the people you follow. It can also turn them back on. . It won't turn off retweets for anyone unless you ask it to.