Looking at some non-theological interpretations of materialism that are not as bleak as the existential crisis brought on by pure materialism...
Many of us rightly try to avoid narrowness in outlook and make allowances for the values and different perspectives of different cultures, as we should. The Vikings believed dying in battle was the surest way to Valhalla, a viewpoint that would horrify Buddhist monks who feel nonviolence is the surest way to Nirvana. But to say any society's values are totally relative and self-determined carries some strange implications.
I had a philosophy/sociology teacher in college who said that social scientists try to adopt the latest scientific paradigm, often with bad results. Soon after the theory of evolution was introduced, some thinkers misapplied such thinking to social situations, creating the horror known as "Social Darwinism". In the 20th and 21st, the theory of relativity in physics resulted in social scientists often feeling all values are relativie---without following that idea to its logical conclusion.
This isn't a theist/atheist distinction. Again, some of the most moral people I know are nontheists. But I venture to say I could mention any number of sitautions or practices, once believed passionately by the cultures they lived in, which you would recoil from, no matter who you are.
No matter how much lip service you might give to "social relativism" there are some things you don't think are relative, but intrinsically wrong.
I'll show you...next week.
Next time: SOCIAL RELATIVISM ISN'T RELEVANT, PART TWO