Let's try to approach this logically -----
Who benefits from a perception of a black-white division?
Who benefits from a perception of a male-female division?
Who benefits from a perception of a rich-poor division?
The simple truth is ... the liberal 'movement' and the Democratic Party are built on the concept of division among the races, genders, and classes. Without the ability to exploit those divisions, the leftist movement has no gravitas. Therefore, no matter the reality, they must create these divisions in order to avoid becoming irrelevant.
They claim racism where it doesn't exist - thus, obfuscating racism when it DOES exist. They tout the sexism, when it doesn't exist - damaging legitimate claims. They claim the rich take advantage of the poor - ignoring reality.
Without these divisions, the leftist movement dies. But, then, who cares? Let's assume that all these prejudices are cured magically. Who suffers? Of course, the left suffers - they no longer have any power, no political message, no gravitas. They become irrelevant.
But, that's good, right? Everybody is equal - everybody gets along!! Wrong. The left so strongly believes in their elitism that they intentionally create systems, processes, and programs that assure these chasms are widened, no healed. Welfare programs ensure a permanent underclass that NEED the elites to care for them. The education system must continue to pump out 'semi-functional idiots' so that the leftist have somebody to care for. Income redistribution must be an ongoing goal, thus the poor NEED the elites to protect them. Women NEED the elites to define, and/or fabricate, the differences and provide them with protection.
Who needs race wars? Who needs sexism? Who needs income redistribution? Who can't afford to have them cured?
The left does ... without it, they are irrelevant.