Atheists and moral relativists cannot do that. Hence our present society spirals increasingly out of control as people are encouraged to believe there is no right and wrong and therefore anything can be done without consequence. Their only option is to use laws to enforce their ideas of morality and to place brakes on behavior. So everything they do not like is illegal. As we can see, they are attempting to extend that idea into the realm of thought.
When a society is united behind or under a belief system, such a the Judeo-Christian one, social sanctions work pretty well, though laws are still important.
Just some ill-formed thoughts....
On the bright sisde there are many sane atheists who acknowledge their debt to organized religion. They know the ethics and morals here are Judeo-Christian in origin and recognize this
Plus many parents of minimal faith send their children to religious schools because they know the children receive a better moral upbringing than the godless public schools
Anyone who thinks that they owe anything to "organized religion" is deeply deluded. Religion, organized or not, offers nothing but departure from God's word. Religion is man's attempt to defeat God's laws and commandments by replacing them with man's softened and blunted alternative, thus condemning billions to eternity in Hell.