The logic follows this track: If the Holy Triune God does not exist, as evolutionary humanists claim, then human beings are nothing but dehumanized products of evolution worth less than nothing. Furthermore, without the one true God, there is no absolute commandment against murder, no eternity in hell to fear, thus no reason not to be evil. This is where we are as a society and why your fears are grounded in reality.
Stuff like this never helps matters in that regard.