I was wondering it seems like when you get a mail app, Android ends up storing that mail address as an account in the account section of the parameters. Is there a way to avoid this ?
This is the user interface to the AccountManager API, which is one of the standard mechanisms to manage auth tokens and background sync. IIRC it's been around since Android 1.0 and it's probably not a useful vector for third-party tracking.
Being the standard way of doing it since beginning of time is just an argument for why it is a useful source to steal contact information and track users.