I tried to do this a couple comments ago, in my second response in the mock conversation:

"Me: When I try to get a handle on what everyone means when they say 'cancel culture', what I think it boils down to is just specifically the desire, or attempt, to quiet or silence someone's voice through the use of some power or influence. The obvious modern example is trying to deplatform people. But a more banal example would be someone blocking another user from posting on their Medium articles. And of course murder would be an extreme example. The idea that that it's a slippery slope from Medium blocking to murder is, to me, clearly absurd - which is why did not anticipate your interpretation at all.

But I didn't see MLK's boycott organizing as fitting into what I see as the real main pattern of what we tend to call 'cancel culture', since it's more about organizing people to send their own message, rather than silencing someone else's message. The analogy I made with MLK's killers, calling their act "the pinnacle" of cancel culture was intended to emphasize the difference between MLK's tactics from the broader spectrum of cancel culture generally that were actually working against him in this case - not to conflate a racist killing with antiracist requests to deplatform."

In short, it was just meant as a way to provide a concrete example of what I mean when I say 'cancel culture' (i.e. silencing a voice), while contrasting it with MLK, who wasn't silencing anyone at all.

Does that make sense? Do you at least see how it could make sense to me?