I regret to announce that I need to actually explain to insufferable people in the notes why 'would you let me say the n-word to save 5 black children?' isn't a clever little thought experiment.
Let's start with a little story:
I work the door at a feminist club sometimes. We've got a big sign at the door in bold letters reading "No touch of any kind without consent, you will be kicked out". When new guests show up, we point out the rule and ask them to confirm that they'll follow this rule.
Every night, there will be a few guys whose response to this is to immediately put a finger somewhere on my body, like my shoulder or my arm, and ask "not even this?". If those guys are allowed to enter the club, they ALWAYS end up groping people. Their response to a boundary that was put in place to prevent harm, is to immediately push it, test it, see if they can do a little bit of harm, see how much harm we will tolerate. That's what that finger and "not even this?" shows.
In this club, little innocent touches without prior consent definitely happen. It's loud and it can get crowded on the dance floor and around the bar. Shoulders touch, people tap each other on their arm to signal that they want to get through the crowd. No harm is done. But "No touch of any kind without consent" stays up at the door because its an effective filter to keep out the predatory guys.
Social conventions around the n-word are a lot like that. While it is technically true that the sound of the n-word does no harm on its own and it's the intent that makes a slur into a slur, to point that out is to misunderstand why the "don't say the n-word ever" social rule is there. It's a test, like our "No touch of any kind without consent" rule. People who see that rule and respond by pushing its boundaries are telling on themselves. They're showing that they want to explore how much harm we will tolerate.
So you're not particularly clever if you invent a thought experiment that shows that the n-word isn't a magic sound that does harm on it's own. We all knew that already and you're not cleverly exposing purity culture or dogmatic liberal behavior. You're just telling on yourself. The "don't say the n-word ever" social rule is a filter that exists to get people like you to tell on yourself.