That toolbar will always show for Super Admins on your site. Unless you've changed the permissions (from the "Options" button in the JFBConnect admin area), no other user groups will see that tool bar. We are planning a 'disable' option for the social toolbar in the next major release so that it can be completely disabled if you never want to see it, even as a super admin.
To completely disable right now, please edit the /components/com_jfbconnect/libraries/toolbar.php file. Around line 17, you'll see:
public function onAfterDispatch()
{
if (JFactory::getUser()->authorise('jfbconnect.channels.post', 'com_jfbconnect'))
{Update that by changing the if statement to 'false' like below:
public function onAfterDispatch()
{
if (false)
{Do the same for the onAfterReturn function at line 44.
That will disable the toolbar altogether until the 6.1 release, due out in June.
I hope that helps, but if you have any questions, just let me know.
Thanks,
Alex