How did 'Space Raptor Butt Invasion' by Chuck Tingle become a Hugo finalist?

They sound cute, but for the second year in a row, politically motivated groups calling themselves the Sad Puppies and the Rabid Puppies have more or less successfully gamed the Hugo Award nominations, some of the most prestigious prizes in science fiction and fantasy. The Chuck Tingle book is one of their recommendations. The puppies oppose diversity initiatives and support lists that are dominated by white men. Their targets, which they call SJW for "social justice warriors," are women, people of color, LGBT writers, editors and artists and the people who support them, including L.A. Times Critic at Large John Scalzi. Rabid Puppies leader Vox Day, a self-described libertarian, has criticized best-selling science fiction writer N.K. Jemisin, who is black, as an "ignorant half-savage," writing, "Unlike the white males she excoriates, there is no evidence to be found anywhere on the planet that a society of NK Jemisins is capable of building an advanced civilization, or even successfully maintaining one without significant external support from those white males."