The reason the current wave of intolerance comes from the left is simply because the new unifying ideology happened to come from the left. The next one might come from the right. Imagine what that would be like.

Actually we don't have to imagine. Left-wing heresy hunting just happens to be more visible, because left wing people have the media and other levers of cultural power. But make no mistake, there's a big time cancel culture within the right, as well. For example, Trump any Romney were both pro-choice until the moment they decided to run for president. Not a coincidence. And these days a preacher in a white evangelical church can lose his job for merely pointing out one of Trump's many manifest moral failures.

While the right wing cancel culture may not be as evident as someone losing their job because they used the N word 20 years ago, it's no less harmful, because it has stifled completely any possibility of having an honest political conversation among republicans. We need our politics to be open in order to have the debates that shape legislation. Right now we don't have those debates, because neither side is willing to say what's on their mind, and it leads to bad laws written by scared people for the purpose of resume padding and not public improvement.

I don't know how this problem becomes more tractable in the Age of Twitter.