The point isn't that McKinsey is solely to blame but that a hugely powerful consultancy firm that expounds upon their higher morals at any opportunity was recommending something that was, at the very least, morally bankrupt (and btw, it was also financially catastrophic for any firm that took that advice in the end).

A great example is Valeant...long forgotten today but the stock went from $10 to $250 to $10, it was a huge story at the time, and was in the news every day when their stock was at the peak. The guy who masterminded this actually worked at McKinsey as an outside consultant for Valeant before he became CEO. This was the McKinsey special strategy: jack up prices, reduce R&D spending, make acquisitions and repeat step 1 and 2 (ofc, there was accounting fraud and the CEO tried to make off with multiple billions...again, this guy was a very senior consultant and was one of the most greedy kleptomaniacs I have seen in corporate life...this is not a coincidence).

Also, this strategy was McKinsey's brainchild. I have seen this over and over where a consultancy firm gets known for their a certain strategy in a certain industry, and they sell it everywhere and it looks like they all just came up with it independently. This strategy was not common pre-Valeant to any great degree, Daraprim happened far after. It became huge because McKinsey were recommending it to clients.

Ironically, I have an almost identical story from another industry. In the early 2010s, some consultant (I never was able to find out from execs who, they referred to an NDA) suggested to housebuilders in the UK that they pull back on capex. These housebuilders controlled a good portion of the land that was available for planning permission in the UK, the industry is heavily consolidated so they control the market for new houses, the market was in massive shortage, and then house prices would go up. Right on cue, pretty much every major housebuilder announces within the space of a year that they are going to begin returning capital to shareholders...in a housing market that is in shortage by roughly 200k homes/year, and in which any housebuilder could have taken massive share in a free market. Either way, new house prices go through the roof (the govt also announces a subsidy program), margins are now 20% against the 5-10% previously, everyone is making out like bandits. That wouldn't have happened if the consultant didn't come along (because the only way it worked is if other housebuilders knew this consultant had been around the industry, and knew other firms would cut back on production too).

Consultants have an absolutely huge role in determining company strategy, and they do deserve blame if they recommend things that are unethical (the fortunate thing about US pharma is that politicians came down on these firms like a ton of bricks, this didn't happen in UK housing). They are totally unaccountable too because when you talk to management, they just refer to some faceless consultant who is pulling the strings...if you are a shareholder, what do you do? The CEO is the monkey, not the organ grinder but it is the CEO who is the public face (and ofc, the Board are totally uncommunicative about what is going on). It is a huge problem because, as happened in pharma, it ended up with lots of companies doing things that were legally questionable and incinerating massive amounts of capital (Valeant had something like $40bn in debt at the peak, and equity was worth near $100bn at peak). ESG investing becomes impossible because there is no governance.