A: Trolling. B: They know people will tell them their question is stupid but they genuinely want to know. C: They are making up a fictional scenario and are only asking the question to see other people's answers, often just for entertainment/as a "social experiment."
They don't wanna reveal their identity as a person may be bcz of the embarrassment of weird ques. And as a caution that no other person of their real life get to know. And all I know this side is made so that you can take opinions on weird question you can't ask someone.