Nice post and you have nailed it.
But it will be very hard to carry out your recommendation. Although your recommendation is rationale the Internet has a long memory and the equally rationale comments by Steve Bannon about the alt-right (the good parts of it) are going to bite us. That is certainly unfair but the MSM has its own rules. Trump has already felt that bite and there is more to come. This should not be taken as knock on Bannon (who I greatly admire) but it is a fact.
My take on alt-right is that it is a strongly conservative reaction to what I believe to be the widely held view that American culture is under attack. I think a lot of Trump voters agree and logically blame the self-serving but destructive Dem immigration policies for it.
This position is easily twisted into racism by the MSM. In November of 2016 that spin didn't work. Now we need Trump to follow through. If he does maybe we won't need an alt-right movement going forward. Until then we do even if we manage to change it's name. In any case there is going to have to be some push-back on the Richard Spencer wing of alt-right. We will see if that happens.