How do I run a GUI app via SSH?
The Mac OS X native application do not use the X protocol for the rendering, but the Mac specific protocol. So you cannot use ssh X protocol forwarding as you could with a Linux workstation.

As you discovered, the reverse is not true, you can install an X server on Mac OS X and have the Linux program appear on your Mac.

What you can do is use either Mac own desktop sharing facility or install a VNC server. Then from your Linux box, you connect to your Mac through VNC instead of ssh.