Slippery slope and fear are favored techniques of the religious too. You're not really teaching creationism, you're introducing students to theories that many, many, many people hold to be true. I think it helps to understand that people can be organized to kill you because they subscribe to unreasonable beliefs. And these beliefs are easily disproved with science. Ultimately, more people will reject religious ideologies as a result. And have reason and knowledge to back it up.