While I don't like twitter (it's so easy to mis-word something, or not have the space to provide the full context) and I DO think a lot of people are WAAAAAYYYY too eager to jump the gun and cancel people...
The thing is, "cancelling" is a completely natural social phenomenon. Humans often resort to tribal thinking, and deviance that's perceived to be harmful to one's tribe is ejected. We do it all the time in our personal lives.
It's only getting so juggernaut-huge because the entire goddamn internet is our society now (and the internet is worldwide and your words are immortally preserved), not just the small world of our family, town, or even state/province or country.
People got full on exiled, excommunicated or executed for saying controversial or mean things as far back as ancient rome. The only thing new about it now is just the sheer massive SCOPE of it all (and the game of broken internet telephone that accelerates it).
Because when millions of people go "hey, you said something really hurtful and dangerous towards a certain group"...It tends to pick up steam, and "feel" like censorship to the person who is being shouted at by a million people who are exercising THEIR free speech to voice their discontent.
Also...As usual, the problem is exacerbated by bad actors ruining society for everyone else. Like...The "ok" hand sign used to just mean "ok", but then a bunch of pricks were like "hey, it looks like a WP, we can use this otherwise innocuous symbol to signal our bigotry in a way that we can have plausible deniability for!". Assholes will always try to find ways to be bigots in an under-the-radar way in public, and when called out on it, will claim their being censored for something innocuous. Subtle signals and dog-whistles are what subcultures DO to find like minded people and express themselves.
And here's the funny thing, Conservatives cancel people too. Colin Kaepernik was full on ejected from the NFL because of the huge furious reactions of the fans when he took a knee at the anthem. Conservatives filmed themselves as they smashed their coffee machines and burned their nikes, and screamed bloody murder about Gilette razors when corporations took a stance they didn't like. So it's clearly more of a societal issue than just "angry libs wanting someone banned because they made a bad 'lulz gay' joke in the 90s".
Hell, those with actual power LOVE to weaponize cancel culture themselves, any time they see some upstart with issues in their past that they can exploit. If the mass media or established politicians see someone trying to dislodge them, they will HAPPILY dredge up something from their past, or mis-represent something they said just to get people to turn on them, even if it was 20 years ago and the person has absolutely proven that they have changed.
Honestly, the only solution I can see is the same one I always tout for things like this.
We need to teach people critical thinking skills at a young age, teach empathy from kindergarten, and then encourage the everloving hell out of those things in our society.
If people empathize more, there will be less assholes and bigots that need to be called out, there will be more sincere apologies for errors in judgement, and there will be more accepted apologies.
If people critically think more, they will do their research before jumping the gun, and less "broken telephone" stuff will happen. Also, people will wait before firing/"cancelling" people under them until they know for sure it's valid.
Sadly, critical thinkers who are empathetic are not easy to control to fit the agenda of the people who run our societies, so....They have no incentive to encourage those things.
In fact, those with power are far more likely to just cave on the symbolism and pretend they've improved things instead of actually fixing the problem. (See politicians focusing on statues instead of "hey, the entire police force needs a complete and total overhaul, there are power hungry assholes in the entire thing who have engineered the system to oppress people with less power and money, typically minorities").
Basically, there's a lot of cowardly groups, business, corporations and schools who don't really believe in progressive values but just do it because it's the path of least resistance. Not out of conviction or because they think it's right but just to not have a mob of shit-throwers on their hands. Those are the ones that need the support.
Seems like you have an issue with Late Stage Capitalism, and the whole "I must sell as much as possible and make as much profit as possible" thing.
Because that's why these corporations often signal progressive values even when they're decidedly NOT progressive. Because they go "Hey, to have the biggest market, we should at least
appear progressive. Because minorities are customers too, and if we add them to the more left-minded people, we think we can sell more if we stick with them".
I assure you, if they thought they could make more money being openly bigoted assholes, most large corporations would at the very least be dogwhistling like no tomorrow, if not actually being openly bigoted. That's how these big businesses work. It's similar for most of the other groups you mentioned too.