If you only allow logged in user can access your Easysocial pages, you can enable this lockdown mode setting from backend http://take.ms/QRrEt .

If you only want to restrict a few pages like group, event, page, people pages, you can create hidden menu item for these Easysocial group, event, page, user menu item from your site backend, then set all these hidden menu access to 'Registered'.

So when the guest user click on it, it will restricted the access on this page.