I agree that "cancel culture" taken to its extreme could threaten the scope of causes EAs could address without facing significant backlash. Matt Taibbi wrote a compelling article on the way this trend has affected our press:
According to your own source, I think your characterization of income inequality in the US as "unexceptional" is misleading. Among wealthy nations, America does appear to be a significant outlier by that metric.
I'd be interested to hear some reactions from EAs abroad on this article's characterization of the American "far left." As I understand it, many of Bernie Sanders' proposals would be considered moderate in Europe, and are certainly economically moderate relative to New Deal Era programs in the US. I think his brand of economic populism is quite distinct from social justice oriented liberalism, although there is overlap between the two.
Finally, when evaluating the risk of an event like the one you're describing, we should consider that establishment politicians appear to be extraordinarily resilient to being "cancelled." Consider, for example, that the presumptive nominee of the Democratic party was able to overcome a well-documented history of racism and the emergence of a #MeToo story that should have been significantly more scandalous than the one Democrats tried to use to block Kavanaugh in 2018. As far as I can tell, corporate-aligned politicians of both parties have been overwhelmingly successful in wielding propaganda to quell significant threats.
That makes sense. The way the article was linked on the rising "far left" seemed to imply it was a concerning trend that young people were supportive of Democratic Socialism, despite the author never elaborating on why that would be a specific risk to EA.
Perhaps it would have been clearer if the risk was broken down as a set of movements or politicians that could spawn an authoritarian government, which doesn't map very well onto a left/right spectrum.