Now that I've seen the final scene on board the PK ship and know that M'Lee was indeed picked up by the PKs, I'm torn on whether or not I should feel sorry for them. They are the bad guys, but I'm not entirely sure if any of them - except for Crais - deserves the kind of death she would deal out.
You have to remember that we are seeing some very unique perspectives. Our main characters, as far as the PKs are concerned, are a bunch of criminals. Much like the Alliance on "Firefly," how can we say for such whether or not they're evil? Because a handful of thieves aboard Serenity tell us so?