It's not quite obvious at all. In fact it's nonsense. It is trivial to demonstrate that a large number of people with materialist views on the world have an abhorrence for capitalism and vice versa with people of a non-materialist bent. How anybody can really believe that there is any causative link between scientific mindsets and capitalism is beyond me and makes me think that they came to their conclusion without actually looking at any of the evidence. For a start there is the glaringly obvious fact that all previous economic systems that we know anything about, which were all much less materialist than capitalism is, were also generally much more brutal and filled with suffering and exploitation for the vast majority of the population and that materialist mindsets have inspired by far the largest and most hopeful attempts to replace capitalism with something nicer. In short, you can only come to the conclusion that the social ills of capitalism are caused by materialism if you ignore the entire history of the world before materialism became a strong influence on human thought. Again and again we find, in history, that by far the most 'pleasant' and human of the social systems for the population have been those where materialism was strongest and spirituality weakest. By the 3rd century BC, for example, the Athenians hardly believed their own god-stories any more and their civilisation sounds vastly more pleasant than anything that existed before - or indeed for almost all of the next few millenia. This is ahistorical, contradicted by all the evidence and logically contradictory. According to the materialist view of the world humans are the makers of their own destiny, all that is good and the concept of good itself has been created entirely by humans. To paraphrase an old folk tale - all glory and honour is ours and ours alone - we even invented the concepts. We are the authors of our own destiny and can do pretty much whatever we set our mind to collectively. Their are no laws that bind us or govern us other than the iron laws of the universe which we can measure and understand. We can, if we so choose, organise ourselves in a way that is as pleasing as possible to as many people as possible. The fact that such marvellous things as ourselves emerged from the chaotic playing out of a box full of sums produces much more wonder and awe than any all powerful mystery ever could. On the other hand, to those who advocate spirituality we are just fleas at the mercy of some mysterious power which we can never really know anything about. Which one sounds like a humanist?