Cheney isn't a piece of history, nor a piece of art. She certainly is not an employee getting fired for what she says or does off the clock. She is someone that was hired to do a job and the business doesn't like what she produces. This is a direct Correlation between duty of a person in a stupid political party and action.
Now if a nurse says she is against gay marriage and people take to the streets to fire her, that is cancel culture because it is not directly associated with job duties, nor is it done while on the clock.