What I call Liberalism is also known as Modernism, and as such has been condemned by the Catholic Church. Moral relativism says that there is no absolute right or wrong. Each person decides for himself what is right. The problem here is that everyone is biased in favor of self-justification. A true moral relativist would have to say that the Nazi's were only guilty of bad taste.
Socialism can mean slightly different things.
In general it means an economic system where the government has unlimited power to control the economy. This can include abolishing private property. Socialism fails to recognize the human right to own property. This right should not be subject to government power. In actual practice, Socialism has never worked.