While cancel culture can address systemic oppression, it also has the potential to ruin someone's life needlessly. Part of cancel culture is looking for evidence by which to mount a person or business's canceling. Often this comes in the form of a social media post, sometimes older posts these individuals or groups may have made. The issue with going through older posts is that they may not reflect the target's values in the present day.
An appropriate example lies in the case of Steven Pinker. Pinker is a linguist and cognitive psychologist who almost lost his status as a distinguished fellow within the Linguistics Society of America over some years-old tweets 
. The only thing that prevented the linguist's removal was that a group of established scholars argued that the canceller's findings did not match up with Pinker's work. If that group of scholars did not intervene on Pinker's behalf, the graduate and undergraduate students would have successfully removed Pinker, ending his career over comments that do not speak to who he is now.