I don't think published authors should ever sue fanfic writers, but I do get how some fanfictions can be annoying to published authors on a personal level.
So, you know H.G. Wells' "War of the Worlds"? A story that posits: "Hey, maybe colonization feels PRETTY BAD when you're on the other side of it, helpless before a technologically superior invader who takes all your resources and murders your friends."
This was a bold stance for a British guy in 1895. Also, there's no triumphant moment where the alien invaders are killed by human ingenuity or human inventions; they are killed by the humble germ.
So I'm sure you're excited to hear about the unauthorized, real-person, fixit fic sequel published by Garrett Serviss, entitled "Edison's Conquest of Mars." Perhaps that title fills you with foreboding. It should.
The plot: Thomas Edison and every other contemporary scientist Serviss could think of (and his self-insert OC) build spaceships, fly to Mars, and commit genocide with Edison's ingenious inventions. The story goes out of its way to establish that the Martians aren't inherently bloodthirsty (it was just their tyrannical leader who made them invade Earth). But Our Heroes indiscriminately kill them all anyway, and take their resources.
Great sequel to the anti-colonization story.