Rene,
The issue you mention has nothing to do with JFBConnect. There were 2 hits when I used your email address in Google: Our JFBConnect demo site and code.joomla.org:
1) On our demo site, we use Community Builder. We had the email field set to Profile, which showed this field to guest users. We agree, this was a bad setting, and have unpublished that from public view. That setting has nothing to do with JFBConnect.
2) Joomla Code is not even a Joomla site, and is in now way powered by JFBConnect. They are simply publishing your email address on that page as xxxx @nospam@ site.com. You'd need to contact them if you want that field removed.
Hope that helps explain, and thanks for pointing out the error on our demo site.. but, again, this is nothing to do with JFBConnect itself.
Alex