Why does Force Quit Applications freeze? When an app freezes on my app, I will press Command ⌘+Option ⌥+Esc ⎋ to open the Force Quit window.

However, this will often take minutes, and clicking on the Force Quit button freezes the Force Quit window and makes the beach ball appear. The window confirming the force quit only shows once the application unfreezes.

Also, if I right-click the Dock icon while the app is frozen, then the Dock will freeze, but it doesn't freeze when I just pass over the icon.

It is also possible to move the application's windows.

So how is it possible for some tasks not to be frozen, while the most important task (the Force Quit window) freezes at any interaction? And what do you do when the Force Quit window itself freezes?
The Force Quit window usually freezes when the system is paging heavily. (Same with the Dock.) Your computer could probably do with more RAM.

You can move windows around when they're frozen because OS X's window manager isn't frozen, and it controls basic window functions like minimize and move.