He agrees with Marx on quite a bit. What he criticizes is:
Treating Marx's writings like infallible holy scripture rather than a 150-year-old text that's one of several important pieces of leftist thinking. Not all Marxists do this, but it does happen (e.g., "the immortal science of Marxism-Leninism"). His argument is along the lines of "we don't call physics Newtonism because while Newton was important, other thinkers have added important contributions since his time."
The tendency of some socialists to insist that people read Marx instead of explaining socialism in more accessible language. If you're trying to teach physics to someone with no knowledge of physics, you don't start them off with Newton. You may not ever have them read Newton's original papers. What you give them is some modern literature that includes Newton's ideas plus the contributions that have been made since. Note that he's on the side of Lenin and Mao here -- they built on Marx with writings specific to their time and place, they didn't just point to Marx until people read him.
These are defensible points whether you ultimately agree with them or not. Deriding him as "lol fancy lad who hasn't read Marx because it's impossible to read Marx and do anything but worship the guy" is dumb and counterproductive. We have to be able to disagree with folks who are to the left of probably 90% of the country without being complete assholes to them, otherwise we're not getting anything done.
He agrees with Marx on quite a bit. What he criticizes is:
These are defensible points whether you ultimately agree with them or not. Deriding him as "lol fancy lad who hasn't read Marx because it's impossible to read Marx and do anything but worship the guy" is dumb and counterproductive. We have to be able to disagree with folks who are to the left of probably 90% of the country without being complete assholes to them, otherwise we're not getting anything done.