The word "cancelled" is often used by plenty of people who "cancel" people, by happily claiming that someone is "cancelled".
The issue isn't just being "called out for being a jerk". It's one thing to call someone a jerk. It's another thing to be entirely unwilling to look at facts objectively, to reason about them, to listen to those defending the person and yet throw wild allegations, as well as vilifying anything an anyone that is in any way close to that person.
Nobody is actually concerned about "cancelling" just because people call each other "jerks". You can call me a jerk if you want. I won't feel cancelled.
I hate that word. It's not being "cancelled". It's being called out for being a jerk, and it's past overdue we did that.
For the Stallman case the impact of "cancellation" was probably 0, anyway.