The political left needs to convince black people that white privilege exists. Therefore, white privilege is a political construct.
If minority communities were to realise that their problems are not due to inherent structural racism, the political left would have no philosophical attraction among minorities. The political left needs the public to believe that the root cause of inequality is not laziness or a lack of conviction and determination, but systemic inequalities. That is how they built a political platform. Without the acknowledgement of institutional racism, they have no electoral power to enter government and “change” it.
The fact that one political party benefits more form a narrative of white privilege than another party, doesn't mean that white privilege is a myth. It might mean that it is exaggerated, but no part of the argument indicates that the concept of white privilege is a myth.
[P1] The political left needs white privilege to exist. [P2] Therefore, the left promotes a narrative of white privilege. [P3] Therefore, white privilege is a myth.
Rejecting the premises
[Rejecting P3] The third premise is not a logical conclusion even if the other premises are true.