I would have thought it was basic common sense to not assume everyone else in the world has had the same life experiences you have. And that it was common sense not to judge or mock people for having experienced a different life.
I have a friend who for his entire childhood had parents who didn't work consistently, lived on government benefits, and did not really parent him at all. He has no idea how to apply for jobs, what normal work conduct is, or all the basics about the job process. Let alone how to interact with managers. How do you expect a person like that to learn your "common sense" about the working world - a world that is as alien to him as a completely different culture, with a language you did not know. It is "common sense" for everyone there to be able to navigate the cultural questions - would you mock someone for not being able to do that effective? It sure would be "common sense" for those living there.
Things are "common sense" to you because of your life experience(s). Consider that others may not share your life experiences (shocking, I know, but this is one of the most common misunderstandings when people mock/demean/judge others, such as your post here). Many people have no workplace experience or role models in their entire life, had uninvolved parents, or are just super nervous given the importance of their job.
Additionally, considering how many people see employee/manager relationships as a clear power hierarchy, where the manager/employer has all the power, it only makes sense people would have uncertainty navigating those relationships. Especially for early career people or those in countries without much or any employee protection.
Isn't this all common sense? ;-)