I think the miscommunication arises when people say "everyone is mooks, even to first level characters."
That's when some people say "that's not as simulationist, because first level characters are obviously weak, too" and others disagree, saying "no, first level characters are better than 90% or more of the world.
Now, we have people with two legitimate takes on setting arguing over something without addressing the real issue. If 90% of the people in a given setting are really worse than first level PCs, then yeah, maybe most people are mooks. In other games where the average level might be closer to 2, 3, or 5, and the players start off at first level, this looks obviously false.
Also, people have different perceptions on how high "Aragorn" is supposed to be, ideally. Yeah, everyone is still a mook, even at 5th level, if the PCs are 20th level. However, if you expect to be Aragorn at 5th level because in your setting, orcs are 1st level, then you're still not communicating the problem.
You're saying (not you, but theoretically someone) that "in my game, orcs must be 1st level, so that Aragorn might kill them easily." Other people say, "in my game, orcs are 5th level, and Aragorn would still kill them easily."
That's because the statements aren't communicating other facts, such as average level (or hit die) in your setting, what level Aragorn is within said setting, etc.
Just my take on a possible miscommunication taking place. Maybe I'm way off base, but I think either side making assumptions might be skipping a step.
Anyways, I'm not saying either side is wrong, just trying to help out. I'm also not judging either play style. As always, play what you like