Discrimination exists but rather than being systemic Campbell and Brauer argue it’s due to a small number of prejudiced individuals.

Discrimination has persisted in our society despite steady improvements in explicit attitudes toward marginalized social groups. The most common explanation for this apparent paradox is that due to implicit biases, most individuals behave in slightly discriminatory ways outside of their own awareness (the dispersed discrimination account). Another explanation holds that a numerical minority of individuals who are moderately or highly biased are responsible for most observed discriminatory behaviors (the concentrated discrimination account). We tested these 2 accounts against each other in a series of studies at a large, public university (total N = 16,600). In 4 large-scale surveys, students from marginalized groups reported that they generally felt welcome and respected on campus (albeit less so than nonmarginalized students) and that a numerical minority of their peers (around 20%) engage in subtle or explicit forms of discrimination. In 5 field experiments with 8 different samples, we manipulated the social group membership of trained confederates and measured the behaviors of naïve bystanders. The results showed that between 5% and 20% of the participants treated the confederates belonging to marginalized groups more negatively than nonmarginalized confederates. Our findings are inconsistent with the dispersed discrimination account but support the concentrated discrimination account. The Pareto principle states that, for many events, roughly 80% of the effects come from 20% of the causes. Our results suggest that the Pareto principle also applies to discrimination, at least at the large, public university where the studies were conducted. We discuss implications for prodiversity initiatives.

The cause of discrimination matters because as Hambrick notes writing about this paper in Scientific American:

 In recent years, the view that most people engage in discriminatory acts because of implicit biases has gained widespread public acceptance. In a 2016 presidential debate, Hillary Clinton commented that “implicit bias is a problem for everyone.” Campbell and Brauer’s findings suggest it’s still not clear the extent to which implicit biases explain discriminatory conduct. (Other work has called into question the validity of implicit bias measures for predicting real-world discrimination.) Research aimed at answering this fundamental question will inform the design of interventions that may one day meaningfully reduce levels of discrimination.

….If, for example, a small number of explicitly prejudiced people are responsible for most or all of the discrimination occurring in a company, an intervention that requires all employees to undergo implicit bias training will probably fail to address the problem. Research suggests that interventions that convey the message that nearly everyone engages in discriminatory behavior may even make the workplace atmosphere worse for marginalized employees, because after the training, nonmarginalized employees may avoid interacting with them out of fear of unwittingly discriminating.