This sounds like leftist claptrap. The true cause of the depression was the sudden calling in of the loans which most people could not pay in such sort notice. The unequal distribution of wealth can not cause a depression all on its own - it is only when less affluent are suddenly made even poorer when the flow of capital becomes restricted.
There are three criticisms of this statement. First, we criticize socialism, which is the belief that a few, so-called elites can make decisions for folks better than they can make their own decisions. Why is the concentration of capital any different that the concentration of political power. A small number of people making investment decisions for everyone, as we have just seen, can lead to enormous misunderstandings of directions, needs, and risks.
Second, production has to be balanced by consumption. Make too much of something no one can buy and you go bankrupt. Was it socialistic of Ford to decree that his workers would earn wages sufficient to afford a car? On a national scale that has to be the case. Too little wealth in the hands of those who provide the labor to produce is just as deliterious to capitalism as too little wealth in the hands of those who will save and invest.
Third, the disparity between those at the pinnacle of corporate power and those who work hard for a living, even highly educated professionals, has never been greater in our history. We have had long periods of great success with relatively less disparity. Given that enormous concentration of wealth at one end is almost universally correlated with crushing poverty, and economic ruin, I am not sure I want to make this claim.
And as we can see before our very eyes much of that enormous wealth was made while creating enormous malinvestment.
So, while I don't advocate redistribution through taxes and social engineering, I also don't think we should just stand by and let the crooks who have created this mess scream socialism when we demand that they bear the cost of the ruin they have created.