What it seems you did was take me saying “Shadowrun is not an entry-level TTRPG” and append “setting” to that, which is ironic given this post.

I applaud your attempt at an Uno Reverso here, but if you take a few minutes to think about this, your gotcha really doesn't work. If I was responding to the imagined claim that Shadowrun is a bad setting for new players then the last thing I would do would be to suggest keeping the setting and losing the system, right? Quite the opposite, in fact.

What I actually did is respond to the claim that "Shadowrun is not an entry-level TTRPG" (which I read as clearly intended to mean the total package of the rules and the setting) by simply pointing out that you can jettison one and keep the other, and that when you do it actually becomes a great entry level game.

The problem here keeps coming back to the fact that you have this weird originalist dogma about roleplaying games where replacing systems is in some way sacrosanct. So when I pointed out that Shadowrun works great without it's legacy of clunky systems, that statement caused some kind of divide by zero error that you could only read as "The rules as fine if you change all the rules" because the notion of separating a system from it's setting seems to be utterly verboten for you.

By your own admission you feel that "It’s the rules that matter in the context of statements like these, not the setting."

Why? I'm sorry, but that's a rule that you made up in your head, not something that's actually inherent to the medium. You're the one who lives in a world where it's more important to say "I'm running D&D" than it is to say "I'm running Eberron." When I think of my adventures in Eberron, I think of my Warforged archaeologist fist-fighting dinosaur riding Halflings on top of a speeding train. I could not, for the life of me, tell you exactly what feats and class features I was using to do it.

I've literally never said the words "I'm running D&D" in my entire life. I've never found it more important to specify a system than to specify a setting. "I'm running D&D" is as meaningful a statement as "I'm running GURPS". OK. So what? Why do I care. Tell me "I'm running Illuminati University" and now I'm excited. Leading with a system is like if I asked you what you thought of a movie you just watched, and the only thing you told me is what cameras it was filmed on.

Whether I'm playing or running, I'm here to tell a story. A story needs a world. The mechanics are completely optional. I honestly don't really care if my character does or does not have a base attack bonus. What I want to think about is why my Warforged archaeologist wears a hat, because that's interesting.

I get that this is not a universal way of thinking about RPGs. For a lot of people they're a set of mechanics to operate and master in the same way that you learn to play something like Magic: The Gathering, where the setting is a backdrop and the cards can be reskinned and re-themed without changing anything about how they play. But I'm gonna be honest, I think it's genuinely sad to see people approach roleplaying that way. It's a hobby with so much boundless room for imagination. To reduce that to mechanics first and foremost is an unspeakably dull way of thinking in my opinion.