Why do you need such wide-ranging GitHub permissions?
Our GitHub integration lets us sync a count of your GitHub commits to your Exist account. Unfortunately GitHub doesn't offer a less intrusive way to access commit numbers, so this integration requires access to your repos.
We've suggested GitHub offer an alternative in future, but for now this is the only method we have available. We don't like it either—we don't want access to anything we don't need! Hopefully GitHub will offer a way to just get a count of commits in future, so we can update this integration.