The lie that almost everyone tells is, "All human life is valuable."
We all know that that's not true. We all know that there are some people who are less than worthless.
Leftists wouldn't relish in calling everybody to the right of Bernie Sanders "Hitler" if they believed that Hitler was a valuable human life. Right-wingers wouldn't relish in calling people to the left of George Bush "communists" if they thought that Stalin was worth a damn.
Rapists, child molesters, serial killers, members of the Green Party, the band Coldplay -- these are all people who aren't valuable, and that the world would benefit from losing.