Yes, according to what the Statue of Liberty says, we started out the misfit country, as did Australia--and in this picture, we're the misfit planet. Well, if the shoe fits, might as well wear it.
Lots of later sci-fi episodes shipped their criminals into space or to another planet--ever see the Botany Bay Star Trek episode? If the planet gets crowded enough, and you're not sure about the death penalty, seems like that would probably happen if you could launch 'em out there.
Little things can be dangerous. Remember what killed the aliens in "War of the Worlds"? Funny creepy aliens in this that should be hilarious, but with the alarming music and seriousness of the actors, the aliens are somehow still scary. With modern effects instead of crude plastic props, this could be a Hitchcock-type movie.
Somehow in The Outer Limits and The Twilght Zone, the bad guys usually get their just deserts, but leave behind uncomfortable questions that make you think twice.
If the Zantis ever do decide to attack us, though, no need for missiles--just an ecologically friendly spray repellent.