I agree that Thune does not see this distinction. Here is my view of the difference:
Hold Accountable: you screw up, you lose your job
Cancel Culture: you screw up, you lose your entire life
Good distinction. My point is that casual conversation is full of these sorts of labels that have widely variable meaning.
"Hold them accountable" vis-a-vis Comey, Strzok, and others ranged from "lock them up" to "expose the truth." The meaning of "accountable" was deliberately vague so as to avoid discussion. Graham would say "we'll hold them accountable," and his meaning was ... who knows?
Same with cancel culture. Some [people think that being kicked off Twitter is enough to justify a claim of being canceled. Others, your definition for example, say cancellation occurs when your life is ruined, but not when you are fired to appease a mob.
"Rule of law" is another code phrase with variable meaning. Rarely is the actual "rule" involved in the discussion. That's too much like work.
With Cancel Culture your family loses their entire lives, as well.