They literally have one commandment against murder (thou shall not kill. Anyone? Anyone?). Genocide much?

It’s better translated as “don’t murder” than “don’t kill” - it uses the Hebrew verb רצח which refers to immoral unlawful killings (i.e. murder), not killing in general.

In Judaism, for example, the rabbis ruled in the Babylonian Talmud that it’s OK to kill someone who is actively trying to murder someone else.

As far as where in the Torah it says to kill people, there’s a bunch of places. For example, here’s one commandment from deuteronomy 21:

If a man has a wayward and rebellious son, who does not obey his father or his mother, and they chasten him, and [he still] does not listen to them, his father and his mother shall take hold of him and bring him out to the elders of his city, and to the gate of his place. And they shall say to the elders of his city, “This son of ours is wayward and rebellious; he does not obey us; [he is] a glutton and a guzzler.” And all the men of his city shall pelt him to death with stones, and he shall die. So shall you clear out the evil from among you, and all Israel will listen and fear.