Why is there no option to sync all apps?

if your on a mac, this is how you would select all apps.

 

If you're on a Mac, select your iphone/ipod/ipad/whatever in the Devices list, then click over to the Apps tab. Make sure the Sync Apps checkbox is checked. Then, while holding the Command button down, left-click one the checkbox for one of your apps that's not already checked. This will check the box for that app and every other app as well. If you Command-click an app's checkbox that is already checked, all apps will be unchecked. So, Command-click is effectively a select-all/deselect-all shortcut for selecting apps to sync.

You can then hit the sync button.

If you're on Windows you'd probably use Alt or Control instead of the Command key, but I don't have a Windows box to verify.

edit: Nice graphic. That says it all!