Great news. The API team at GitHub have been busy over the last few weeks and have released a whole series of new, more granular oAuth scopes.
What this means is that we don't need to ask for write access to your profile in order to use Gitter. Huzah!
For new users, just head on over to Gitter and once you click signup you'll see the new oAuth permission request.
Existing users, just sign out and then log back in again and you'll see the change to permissions.