Justine Sacco was definitely canceled, in exactly the way you are denying happens. There is a legitimate discussion to be had on the phenomenon, and it can't be hand-waved away by claiming it's completely legitimate. Clearly it's not.
The fact that real things happen doesn’t make using the same term to describe not real things happening acceptable.
I can’t call out of work because there was a blizzard if there wasn’t a blizzard recently where I actually live
Cancel culture is a real thing. It's a new thing enabled by the structure of the systems we've only just created. I think a label is justified (even if this one kind of sucks). And of course concept creep will find this label weaponized almost as soon as it's been created.
That's kind of the era we live in: bad faith abuse of language by the extremists on all sides.