This is not corruption, it's just favours.
Nobody is awarding a major contract to get their kid an associate job at McKinsey.
The contract is awarded to McKinsey, if the person holding the purse has someone looking to get into such a role, then it's a nice thing that McKinsey can do in return.
My mother was a director of customer service and used to hire all of my friends in high school ... because they were my friends. It's normal.
It's technically not very above bar, but it's not necessarily corrupt. Most people get jobs through their networks, this is 'kind of' that.
Relevant article: https://www.wsj.com/articles/in-growing-saudi-business-mckin...
The Saudi government is not giving McKinsey huge contracts because so and so's kid got hired there - point blank.
Also remember these kids are already stinking rich they don't even need to work.
And it's also a part of the world where business is done on the basis of relationships.
When a firm is giving Ferraris as 'kickbacks' then it's corruption but not this.
Hiring less than capable individuals while excluding more capable individuals, for the sake of obtaining contracts, in a region where ministers are changed on a regular basis (hence no guarantees of the connections staying forever) is exactly what I'd call a kickback.