On one hand you have Keynesians who want to screw the rich out of envy and spite and have no concern for the poor, or even worse, actually want to oppress the poor to keep them as their constituents.
On the other hand, you have, like in your example, capitalists who think of the poor as an inferior species to be ignored, or worse, eliminated.
Neither side is immune.
I mean think about this. We're talking about an increase of 4% in the marginal tax rate for those making above $250k/year. A rational argument would be to look at the impact of where these tax dollars go versus what the wealthy might do with it. In itself this should be a very innocuous discussion. But look at what we have.
This is not about the best way to make the world a better place. But I do think it is more about "who _deserves_ to have resources".
Of course greed and self-interest is part of the motivation for making those arguments, but most free market economists and supporters truly believe that by allowing the rich to keep their wealth that all of society will benefit. Rich, poor, everyone.
You may disagree, lots of people do since at face value it is counter-intuitive, but my point is just that a lot, probably the majority of free market supporters, actually do have the benefit of all of society in mind. They'd say that the 4% increase in marginal tax rate would actually be detrimental to the poor. Again, you may have excellent arguments for why it is better for the government to take and spend that money, but they have logical counter-arguments.
In Reagan's era they would pitch trickle down as how everyone benefits from these tax cuts. The actual stated goal was to make life better for everyone, but starting from the top.
The current stated goal from the right is that the rich deserve the money, and the poor do NOT deserve. Not that the tax cuts will have some side benefit to the poor. Rather that we need to keep the money out of the hands of the poor. This is why the constantly use the code word "welfare" when talking to their base.
Again, there is a very rational argument to be had here. In fact, I think a rational argument would be a very boring one for most people in the US. But I think the reason that everyone is up in arms is not due to their passion for capitalism. But rather I think there's a fundamental belief that there are certain groups of people unworthy of _their_ money.
And I think you've seen some of this in statements from people like the lieutenant governor of South Carolina, when he said, "My grandmother was not a highly educated woman, but she told me as a small child to quit feeding stray animals. You know why? Because they breed. You’re facilitating the problem if you give an animal or a person ample food supply. They will reproduce, especially ones that don’t think too much further than that. And so what you’ve got to do is you’ve got to curtail that type of behavior. They don’t know any better."
Their belief isn't one that they can make the world a better place. But rather of actual superiority (hence they shouldn't be forced to give resources to inferior people). This I do think is a fundamental difference.