Postal 2 is a postmodernist interpretation of free society's thinking and the power of choice.
The Postal Dude is not merely a protagonist for the player to insert him/her/xir/self into the game world; rather, the Postal Dude is a vehicle for the narrative to be told and the experience to be had.
When the player is in control of the Postal Dude, the capability one has is fully realized. The Postal Dude's rationality of the actions he takes is reflected back onto the player, i.e. any action is relegated to everyday occurrences, and the context is lost in lieu of gratuitous violence and chaotic entanglement. Through this constant repetition, the message emerges from the chaos and the player is imparted with clear knowledge of what their actions truly affect.
One has to question the greater societal implications when traversing Paradise and enduring the day to day livelihood of our narrative vehicle. Along the way you may finally come to the following question:
Are our actions truly our own or do we transgress our power of choice into a character, or are we merely the vehicle for the Postal Dude within our own narrative?
Now ask yourself, does any of that sound like a mere joke game?
And if it does, how many joke games supply that much commentary, depth, and rich content?