I notice that the response is not uniform across liberal issues. The practice of getting someone deplatformed, fired, shunned, or otherwise punished is used by some causes but not others. For some, saying anything even mildly positive about Donald Trump is enough to get people up in arms to get that person cast into the outer darkness. That is person-based rather than issue-based and I don't know whether there is anyone else that attracts this. Who will inherit this? Mitch McConnell, perhaps. Ted Cruz, maybe. Though even if The Donald does not win enough appeals to remain president, he will likely remain visible and good copy even for those outlets that hate him, so he may retain the status of lightning rod.
PETA does things that annoy me, but I don't recall them engaging in cancelling their opponents. Environmental causes in general have a tendency to quiet (but effective) defanging of those who disagree, but I don't see that vindictive destruction as much from them either. There is more cancellation around climate change than all the other fresh water/clean air/wildlife preservation causes, but even then, not the usual focus of those folks. CoVid is more of a ridicule and censoring than a personal destruction issue as well. Abortion and sexual assault, the so-called "women's issues" have not attracted the same type of energy, unless it is a conservative man who is accused of an actual assault. Statements which infuriate liberal women don't quite meet the threshold, though they do attract heat.
There is some tendency for people at colleges, both students and
teachers, to call for the cancellation of anyone about anything, but even
they strongly favor some issues over others. I admit I am getting my impression from the few conservative and fewer liberal sites I frequent, so it may be a ridiculously biased sample. What is happening on actual campuses I would like to hear.
So what issues are the cancel culture issues? Trans issues, and to a lesser extent gay issues. African-American issues, especially as they relate to criminal, disciplinary, or those elusive "respect" issues for people who set themselves up as authorities and spokespeople. Hispanic or Native issues, not so much. Those are given lip service but don't attract quite the ire. Prejudice against Islam? That seems more mixed, but maybe that one makes it into the top tier as well.
I may have read this wrong. Look over the landscape and tell me what your elf-eyes see, Legolas.