It's a "red herring" or "strawman" argument ... Trying to equate unborn fetus as a human life, and thus it is hypocritical to be "okay" with taking the "life" of a fetus but be against the death of a terrorist.
Sounds like the phrase is referring to liberals or democrats. They are for abortion (which I and many more consider killing) but they don't want to kill terrorists. They'd rather "negotiate" or appease them instead.