Yes, they blew up a planet - so why the hell do you need FFG to hammer home the fact they're evil? Yes, perhaps by the standard, most of the Empire is evil, but a lot of players and GMs want to explore BEYOND that single-minded, black and white possibility and delve into a more realistic scenario.
Heck even TCW did that, legitimising desertions and nigh on genocide, and if I recall correctly the use of flamethrowers, by orders of Jedi...