It seems that you didn't even read three paragraphs into the article:

"At times, McKinsey consultants helped those drugmaker clients fend off costly FDA oversight — even as McKinsey colleagues assigned to the FDA were working to bolster the agency’s regulation of the pharmaceutical market. In one instance, for example, McKinsey consultants helped Purdue and other opioid producers push the FDA to water down a proposed opioid-safety program. The opioid producer ultimately succeeded in weakening the program, even as overdose deaths mounted nationwide."

McKinsey was actively helping opioid manufacturers minimize government oversight. The misconduct in question by McKinsey isn't hypothetical.