I agree that it's not that productive to say that things would be much better under Hillary, even though it's immediately, blindingly obvious that the statement is true. She's not the president, we somehow elected a villain out of a saturday morning cartoon, and we have to live in that reality.
On the other hand, the op-ed sabotages itself by using that statement as a framing device, simply because the statement is so obviously true. So I'll take a stab at ignoring the framing and see what's left and what I can get out of it.
As I read it, the piece seems to be arguing for a sort of racism accelerationism, essentially saying that Nazis openly walking the streets is good because now we can acknowledge that racism exists and work on the problem. Ok, yes. With Nazis openly walking the streets, it's very very obvious that racism still exists. But is that actually helpful?
The thing is, we've always acknowledged that racism exists. The problem isn't acknowledging that it exists at all, it's acknowledging that it exists in us. Everyone thinks racism is someone else, something else. "No, racism isn't me hating welfare, it's people in white hoods burning crosses." Does having actual people in white hoods going around burning crosses help with this problem? Or does it let people point in relief and say "there, that's racism. Not me, I'm a good person, now let's get on this problem of voter fraud and restart the War on Drugs."
I'm not entirely sure what the answer is here. Does having Nazis out there and seeing the president support them make people reflect on themselves a bit more? Does it end up helping? Maybe, though the scenario I outline above seems a bit more likely to me. People are bad at self-reflection and good at deflecting.
There's also the question of knock-on effects on other extremists. Does seeing white supremacists and Nazis out there marching, and seeing the president tacitly support them, embolden people who feel the same way? Is this balanced out at all by seeing the pushback from reasonable people? Again, I'm not entirely sure what the answer is, but given that we've seen at least nominal pushback against this kind of overt stuff for years it seems likely to me that seeing the marchers and the support from the president would have a larger effect.
In short, even ignoring the poor framing, I don't think the op-ed is really correct. It doesn't engage in much depth with any of this, and I'm not sure how much the author considered these different possible directions.