Explain the relation. How is racism used to control the economy and how would that control be lost if there was no racism?
So I'm gonna break up the responses into multiple posts, since they're fairly complex topics. For this post, let's just look at this question.
Racism is a regarded as a particularly vile sin in American social norms due to its history of slavery. What I'm about to describe only applies to the US, and to a lesser extent, Canada.
To understand how Capitalism uses racism to exert control, first we need to look at how Capitalism exerts control in the US. I see three main vectors of control: elections, lobbyism, and media. First, with elections, we can see that American politicians aren't actually beholden to the people who elected them, but rather to the people who financed their election campaigns. Elections are less about the performance record of a particular candidates, but rather how well their election campaign is run. To run a good campaign, you need money. Lots of money. That's where the Capitalists come in. The money they give to particular politicians to run their election campaign always comes with the understanding that once elected, that politician will use his powers of the office to reward his donors.
The second vector, lobbyism, comes in two stages. First, there are the benefits that a politician can get right away, while they are in office. These can include dinners at expensive restaurants, tickets to entertainment events, and even under-the-table cash incentives. Then there are the rewards a politician gets after they leave office, provided they've served certain special interests well: cushy jobs at mega-corporations, lucrative speaking fees, or some kind of board position at various NGOs.
The third vector is through control of the media. We're all familiar with how Fox News conducts character assassinations on "leftist" politicians, but really all the media do it. Step out of line, and a politician might suddenly find themselves in hot water over a decades old liaison, or maybe their less savory activities suddenly gets exposed. Or maybe it's as simple as shutting them out of the limelight.
So how does Racism play into all of this? Since we've established that the Capitalists run the show by controlling the politicians, Racism provides a way to exert that control by creating division.
For example, gerrymandering is the act of manipulating electoral boundaries to favor one party or class, and that is only possible if there are existing divisions to exploit. Since people of the same culture and ethnic group tend to congregate in the same region, Racism provides an easy way to geographically divide people on their political views. The vast majority of black Americans vote democrat, and this could be exploited in a number of ways. You could redraw the boundaries so that black Americans are always the minority in an electoral zone (or the majority, depending on what you want to achieve). You could use existing racial tensions between, say, Asians and blacks, to manipulate one group into voting the way you want. For example, the whole college admissions scandal. Are Asian parents blaming the white people who are keeping Asian students out on unfair criteria? No, they're far more likely to blame the black students who benefit from affirmative action.
Creating divisions among the people also has the benefit of distracting them away from what you're really doing. Obvious example: blaming China for IP Theft, currency manipulation, climate change, the coronavirus, and now genocide, has made most Americans completely oblivious to the fact that their infrastructures are crumbling and their politicians are enriching themselves at their expenses.
Look at the way the right wing media attacked Obama. Accusing him of being a Muslim, of being born in Kenya, or secretly working for al-Qaeda. Obama was basically a lame duck during his final years, and his healthcare reforms were ultimately put in the dustbin. Now I'm not saying racism was the only reason Obama lost control of both houses, but they were certainly additional bullets in his opponent's arsenal.
Today, we can see racism being used to shut down opposition voices to wrongdoings. Voice opposition to the Israeli pogrom in Palestine, and you're labeled an anti-semite. Chinese Americans are being singled out for their ethnicity and ostracized if they dared to speak any word of support for their homeland. In this current environment, I would argue it is far easier to voice support for China as a white or black person than it is to do so as a Chinese person. In this way, consent is manufactured, and the interests of those doing the manufacturing are advanced. Who benefits? The MIC gets to continue sell more weapons to Israel (operating that Iron Dome ain't cheap!), Apple and Google gets to hamstring their major rival, and Exxon Mobile can continue to siphon oil from Iraq.