Sir Julian Huxley: Humanism is a religion
‘A religion is essentially an attitude to the world as a whole. Thus evolution, for example, may prove as powerful a principle to co-ordinate men's beliefs and hopes as God was in the past. Such ideas underlie the various forms of Rationalism, the Ethical movement and scientific Humanism.’
‘Humanism: An outlook that places man and his concerns at the centre of interest. Modern Humanism, which does away with traditional Christianity, is characterised by its faith in the power of human beings to create their own future, collectively and personally.’
Growth of Ideas. The evolution of thought and knowledge. Ed. Sir Julian Huxley, 1965, pp. 99, 336.
In other words, evolution = religion. That is, people (not God) set whatever rules they want. In practice, this usually becomes 'might makes right', including the tyranny of the majority.