There's a very clear line.
Let's look at a local example in N.C.
A town council member votes against the expansion of a low incoming housing complex. At the time of the vote he states that the complex would be detrimental to the surrounding community (the direct neighbors are petitioning against the expansion), and the people living in the complex were lower income and needed to take personal responsibility to reduce the litter blowing out of the complex (both of which are documented).
Tell me which of the responses below is civil advocacy and which is cancel culture.
- A group of citizens in the town protest the council member's vote outside of city hall, contact all the council members email addresses outlining their dismay at his remarks, contact the local TV station and news papers to let their dismay be known. Demand a retraction of his comments that possibly appeared to imply that the people in the complex were responsible for being low income and were litterers. These town citizens organize their protest and emails online via a Facebook group they create and a Twitter handle used for coordination of events. The council member later clarifies his statement after the response of the community.
- A group online that primarily includes people who don't live in the town - call the town council member a racist, demand that he be fired from the town council. They organize on-line by tweeting in every thread possible with hashtags what a horrible person this council member is while spamming many Facebook and other groups with misinformation. The quotes they attribute to the council member are false and are spammed all over the internet by a dedicated group of people. These individuals dox the council member's home address and phone numbers. The council member's family deals with threats coming in on their home and cell phones at all hours of the day and night... while their teenage children get threats to rape them over text as well as sexually oriented pictures. One evening a firebomb is tossed on their porch which makes the council member's house unlivable. The town council member who had served the town for over a decade quits the council and moves out of the town.
So tell me which of the above is civil advocacy and which is cancel culture.