Marx was wrong about almost everything he ever wrote about economics, not least that capitalism would eventually spiral into destruction and ruin, but his thoughts on commodity fetishism, whatever that means, have to be among his worst work. He was obsessed with the impacts of labor on the economy; so much so that he misattributed all sorts of things to the value of labor.

The entirety of the section of Das Kapital that you linked can be summed up thus: resources, when the mysterious ingredient labor is added, become something more ... and then we worship them. What they become, of course, is commodities, and the reason we give commodities more value is that they have been imparted with uses by labor. Marx says that these commodities, in addition to having uses, create a sort of social connection between producer and product. (Think Geppetto and Pinocchio, an imperfect allegory.)

The problem is that he then goes on to say that not only do we place value beyond that which physical manifests itself into these commodities, but also that this is a bad thing. I can think of many times in which I might "fetishize" a commodity, with no sinister underlying motive. A stuffed animal that I've had since birth, worth less than nothing on the open market -- but if I lost it I'd pay $20 to get it back? Total fetish there.

Capitalism is simply not the religion of greed which Marx seemed to believe it was, and that clouds all his writings.