It seems to me that your reasoning here mixes egocentric thinking, black-and-white thinking along with mind-reading.
Egocentric/Black-and-white: When interviewing people, the interviewer usually doesn't care about individual performance but about how different interviewees compare with each other. If something is a question that's hard for everybody to answer,
Mind-reading: It's possible that the interviewer didn't cared at all about your memory but cared about your ability to give decent answers when you don't know the technical details of what you are asked about. That seems to be a skill that matters to a product manager.
Thank you for the answer Christian - The objective isn't really to check if the interviewer is fair or unfair. Whether he is committing a logical fallacy with his knowledge or without his knowledge is out of the question. He might not be doing this deliberately. He might genuinely assume that all interviewees for the role must be aware of the generic stuff. We are not trying to understand the interviewers mind, but a simple error in asking generic questions for a specialized role. In fact, it is one of my friends who went for the interview, let me quo...
Recently I went to a product manager interview.
They asked a few questions, for which I gave the answers. But eventually one interviewer asked extremely trivial questions i.e. first year of graduation questions - How does the wifi router work? How does DNS work? How does internet work? These questions are so generic, trivial and basic but at the same time, nobody can remember everything. These questions do not require you to use your logic either. It is a simple memory based question. But since I wrote the answers to these questions over 10 years ago, it is impossible for me to remember them. I understood the bias at play here, but I could not give a name to it. There might be multiple fallacies or biases at play here. Can you please help me pin point them?