The basic fallacy of Marx is his belief that humans are basically good and that some external evil leads them astray. In truth people are people; some will give you the shirt off their back, while others will kill you for your sneakers. And worse then that, we are inconsisten - the same individuals who are capable of noble selfless even heroic deeds are also capable of doing evil.
Capitalism does not create greed and other human failings. The short comings are there, it is a truely worthwhile calling to try to rise above those shortcomings - and I find it has been a lifetime task.