I liked the Guardian article, as it made me think about the issues. I have no familiarity with this book or its author so I can't comment on that.
But I am interested in the role of the relatively new information technology here:
It's social media which allows the cancel culture and similar phenomena to exist, it makes us feel as if the distance between authors and their audience is removed, and pile-ons, for instance, are often interpreted in statistically incorrect ways as demonstrating extremely widespread disapproval of a particular book or issue or person which they may not be.
The majority of people are not on Twitter, for one thing, and those who do respond to various issues are usually the ones who have most extreme feelings on a particular topic, from both end points of various distributions.
I believe the polarisation of opinions comes partly out of this aspect, especially when Twitter disapproval is viewed as disapproval by the majority in the relevant population (say, readers of particular types of books) whether it is or not.
Because pile-ons work, they can also be manufactured rather than seen as something which occurs organically, though of course they can be the latter, too. Political movements have learned to use them pretty effectively, to further certain interpretations.
It's almost impossible to successfully stop a pile-on from happening (think of a Gish gallop carried out by a couple of thousand accusers, all at the same time, and you can see how responding to the accusations really is impossible), and whether it can be justified by some ethical criteria or not, the effect is always at least mildly unpleasant and sometimes far worse than that on the attacked person or organisation.
Because pile-ons can destroy reputations and are so difficult to cope with, employers of those who have been attacked and the industries in which an attacked person works etc. have strong incentives to disassociate themselves from the opinions causing the pile-ons to happen so that they don't get contaminated by being associated with the issue.
In some ways the 'court of public opinion' has now been transformed into something rather different: more partial, perhaps, though also more open to those whose opinions were previously not listened to, but also with much stronger powers to sentence someone to at least a loss of reputation.
There have been cases where probably an entirely innocent person lost his job due to something like this, and we are quite likely to see at least some where this will happen in the future. (I also know of a case where someone with the same name as a canceled person got nasty attention from various social justice warriors).
Which individuals might be unfairly sentenced by the online opinion courts will depend on which groups wield the most power in a particular society at a particular time. As far as I can tell, the cancel culture is currently used more by the political left in Western countries, but it has certainly been used by the political right in the past and can be so used in the future, too.
I have no idea how any of this could be moderated, but I do feel that instant responses by employers, organisations and so on are a very bad knee-jerk response. If this is now going to be the new court of online opinions, proper evidence should be examined and the accused should have a barrister to defend them, too, and there should be some kind of a court of appeals.