That is not what the article states...at all. The authors sought to examine the formation of price bubbles, and no surprise, homogenous market conditions lead to the formation of price bubbles. This is literally talking about the alignment of services and pricing strategies, taking into account how acknowledging ethnic diversity leads to better tailoring of pricing and services. This is like saying water is wet. If I take the time to understand my client, of course I will better price my services.
You've also failed to address how organizations can provide diverse services, and be successful in targeting diverse market demographics, without themselves having a diverse workforce.
There is also nothing in your article that talks about the ROI, which is ultimately what drives such investment decisions.
You are also overlooking the extensive articles in Harvard Business Review and other scholarly journals that empirically explain the failure of workforce diversity initiatives.