I agree with this statement as well. That’s one thing the original article got wrong. 100% of Trump’s support was due to racism — whether due to active racism such as that of his KKK and Neo-Nazi supporters, or due to the passive racism of those who elevated their own concerns and issues over that of the existential concerns expressed by members of other races and religious minorities.
I think this dovetails with the idea that Clinton never really addressed racism directly. At best, the issue was indirect vis-a-vis the critique of Donald Trump’s campaign as racist. But pointing out that Trump was racist does nothing to address the every-day racism that disadvantaged groups face in America today.