The page from sc-1 image is only for joomla users. "Custom Database Columns" area are only for custom columns from #__users database table. If you add custom columns in Joomla users table, you can export that columns too.
For JomSocial export, please click on "Export" - "Export JomSocial Users" menu item (this menu item is available only if you have installed JomSocial extension).
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