I no longer consider any manager to be 'professional' if they get so dogmatic and process obsessed that they underline the word 'must' before asserting the need for a given practice or methodology.
Well, your opinion would be in direct opposition to the processes employed by NASA to reach insanely high code quality. I found an article from 1996: The Write the Right Stuff. Although they do agree creativity is stifled, it does indeed result in better software.
And I, as a professional programmer, think there are certain _must_ practices. If you fail to do these things, you aren't doing a good job and you aren't acting as a professional (e.g. documentation, source code management, testing). For small trival activities these aren't necessary any more than a builder needs a blueprint or safety specifications for a dog house. But if you're building an office building you better include the necessary processes and cut out the "creativity" that might kill someone.
I do think there are two pressures that negate acceptance of the sort of process that NASA uses to produce such great software. The first is that it can be boring. Most people do not like their jobs to be boring, even if told that it's important. Other industries have regulations that require engineers to do boring work. Software developers are not subject to any such requirement unless the company mandates it (e.g. ISO9001). The second is that, unlike NASA, most software companies are competing for customers at a cost of time and money. And customers generally accept "good enough" software as long as it is cheap and available. Cutting corners to meet those demands is an obvious result, just like teachers cut corners to meet test requirements or banks cut corners to meet earnings expectations.
So I expect your opinion, produced from the varied experience in the tech sector you cited, is that the process gets in the way of you shipping and generating a profit. That's a valid argument. It is also valid to argue that many agile processes will not produce better software, when employed by some people. However I do not agree that a manager is unprofessional to mandate a process and fire employees who do not comply.