Maxine Udall says, "I pretty much hate it when Marxists make sense. ... I was relieved that no (Marxist) solution was offered [in the linked video]..."
This is a Very Bad Attitude. I suppose we should give Ms. Udall some credit for at least listening, and admitting (however grudgingly) that David Harvey has correctly identified a problem. But no honest seeker after the truth should ever "hate it" when anyone makes sense or is correct about anything. And even if one does hate it, it's not the sort of thing that one should admit; it should be a shameful secret that one does one's best to hide and ostensibly pretend doesn't exist.
I'm a militant atheist, but I don't "hate it" when the religious are right, and I'm never "relieved" when they don't offer a solution to a problem they correctly identify. Similarly, I'm a revolutionary communist, but I don't "hate it" when capitalists, reformist socialists or anyone else is right about anything... even revolutionary communism. If they're right, they're right, and I'm positively grateful for learning a new truth. And, if they offer a capitalist or reformist solution for some problem, good for them.
I'm not critical of religion because I'm an atheist, and I'm not critical of capitalism because I'm a communist. If that was the case (and I were willing to admit that was the case) even a little I would feel obligated to simply hang up my skeptical credentials and become a wholehearted ideological partisan.
I am, rather, an atheist because I'm critical of religion, a communist because I'm critical of capitalism. I've looked as carefully and honestly as I can at both systems of thought, and found them false at their core. They can be and usually are — to a certain extent — "fixed up" — their fundamental flaws mitigated — but it seems to me to be more sensible to correct the fundamental flaws directly.
Yes, you can create a humanist ethical system on top of belief in a God, but there is no God. Why "fix up" theology when you can dispense with it altogether, and build a humanist ethical system on top of nothing more controversial or supernatural than that people do in fact value the well-being of others?
Yes, you can create a more-or-less efficient and just economic system on top of the private ownership of capital, but the private ownership of capital — especially finance capital — introduces a fundamental inefficiency and injustice. Take out these fundamental problems and there is nothing to "fix up".
The "militant" atheist argument against moderate religions is very much related to the revolutionary communist argument against reformism and liberal capitalism. Yes of course liberal capitalism is better than laissez faire capitalism, but liberal capitalism implicitly affirms a fundamental tenet of laissez faire capitalism — that capitalism should be privately owned — while simultaneously compromising that principle by advocating regulation of "privately" owned capital for purposes that in no way enhance the benefit of the owners. (Note that regulation for some mutual benefit that includes a benefit to owners enhances and does does not compromise ownership.)