BuddyPress.org

I’m still not clear about your issue. Do you have any screenshots of what the homepage looks like when logged in as Site Admin and then what it looks like when logged out? After logging out, please clear your browser’s cookies and cache just to be absolutely certain you’re looking at a newly-refreshed page.

All your members should be able to see the sitewide activity stream. That is what it’s there for. On the link you provided, I can see three activity items on the homepage.