The blame is meaningless to them and has zero negative consequences (in fact it has positive consequences), they just perform the part of "evil" management consults. It's an important part in making sure no one takes too big of a responsibility hit.
This is what makes McKinsey so vile. It's not that they actually put these ideas in the heads of their clients, but that they perform a necessary part in making sure that even the most banal of evil actions to the most horrendous can remain ultimately consequence free.