If there is a position which is novel, where there is no known advocate (either individually or as a group) to represent it, then imagining why a theoretical person might take that view can be helpful. However, this is the age of the internet, where finding people who genuinely hold the most outlandish of positions is really quite simple. Why do I need to imagine or speak on behalf of another person to present their argument for them? If they are not an adequate representative, and are merely parroting ideas, then surely they will be able to point me in the direction to the source of those ideas.
There is a lot of discussion regarding appropriation thrown around these days. I find that it's often applied to situations where empathy is very possible, and there's nothing keeping many of us from understanding other's positions. But if instead of genuinely asking them to represent their own, and feeling that my attempts to speak for them are just as sufficient, or an even better means of expressing an idea, which I freely admit I disagree with... that's some arrogant shit right there.
If one is so egotistical that they believe only they can adequately present opposing views, instead of allowing people who actually hold those views to do so, then what chance do they leave themselves to grow and learn? And that is putting aside the card stacking tactics playing at steelmanning, which is perhaps even more common.
I am not a flat Earther. I think they're wrong about reality. I can explain why I think they're wrong, but I would not presume to know why someone might or ought to be one. There is no way for me to honestly do so. Pretending like I could would not help me to convince, learn from, or relate to anyone holding said position. Merely playing at being an advocate for an idea as a thought experiment is not a heuristic that bestows enlightenment. It gives one the false impression that they understand people and ideas which they do not.