They don’t.
Atheists think that believing in God is the same as having a lucky rabbit’s foot or believing in the tooth fairy, so basically they think believers are stupid. They often don’t mind ridiculing believers in a public way, like at school or the work place. Where do you think bullies come from? It is Christians who are taught to love their neighbor, show mercy. This point is important: just because we will disagree with someone does not mean we hate them. Christians are always accused of hating when it’s the finger pointer. When an atheist says they are not respected because they think abortion is a woman’s right, they are totally blind to the fact that babies are human beings taken to be slaughtered. What can you possibly say to pierce that dark heart, that cannot see the human person in the womb? Only God can. Lord have mercy on us.