How can people deny evolution?

In my church youth group they were scoffing evolution, and saying how it couldn't make sense I was joining in half-heartedly but I realized I find it ridiculous for people to say it doesn't exist, my parents are the same, I am a faithful christian but I completely believe in evolution through the process of natural selection, they don't understand that evolution is god's tool for life. and it makes me realize why peopel think us christians are idiots.