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I just tried it at your site. the module at built in jomsocial positions respected the access level.
for displaying the module, jomsocial using joomla function (because jomsocial running under joomla).
could you please make sure about this issue? it can be cache, please clear any cache first after made some changes.
I've just set a module to position js_side_frontpage_bottom on super user access and cleared server cache. Clear your browser cache and navigate to frontpage as guest and you will see ....
I will leave it this way for the next few hours for you to test.