It’s influencers targeting “outsiders.” There have always been outsiders, whether in the 70s, 80s, 90s, 00s, etc. Sometimes that’s even healthy. But because that only became a source of strongly-defined “identity” and “pride,” often people in the past would grow out of it or use it productively (as a source of empathy for other outsiders) and leave only a small dedicated core group who were vulnerable to being exploited.

The difference is that now these influencers indoctrinate a vulnerable audience at the right time, and coach that audience into making alt-right talking points a part of their identity. Social media then allows those new recruits to see each other and create a community that self-reinforces.

There is no equivalent push on the left, because the left assumes that sense will eventually prevail. It was true decades ago, but now there is no reason to believe that - those indoctrinated never have to confront their doctrine, they live surrounded by it.

So yep, it’s going to keep growing. The only solution I can think of is to regulate news media to penalize lying and propaganda. That itself is nearly impossible to do right, since it will be abused by every right-wing leader if there is any opportunity.