McKinsey (or whomever) is only motivated by money and are loyal to whomever they understand the principal to be. Given an idea or concept, you’ll have reasonably competent people running it down, backed by people who grind out tight PowerPoint stuff overnight.
It basically boiled down to “now that I’m a member of the engineering team, I’m expected to participate with the processes that are in place”. When I was a consultant, I was generally brought in to solve problems caused by those processes breaking down. Not sure why they couldn’t square that circle, but I went back to consulting 6 months later and retained them as a client, wherein they started taking my advice again and not throwing misguided projects at me.