Because exploring their interests is what filmmakers do? Because he thought it was relevant? I mean he did make a movie about a guy manufacturing a bullshit war for political gain a year before Iraq after all. Authoritarian governments was one of Lucas's main themes since THX, so making the creation of one the backdrop to the prequels isn't unfitting.
It might be fitting for his interest as a filmmaker. It's not fitting to watch in a Star Wars film.