Don't conflate what you'd want to be true :
with what is actually true. The truth doesn't necessarily fit with your worldview. This :
is true if you put some limit as to what "not mainstream" means. Some horrible person invented the term, then some slightly less horrible people used it to brand themselves and a few others. Then they tried to build up a coalition of non-mainstream right wingers under that flag. Many people on the left tried to warn everyone that it was dangerous, and so did some "centrists" but the right didn't listen and became mostly united behind Trump and the alt right. Because Trump is the leader of the alt right (or at least someone very close to the alt right who is pushing some of their agenda), people on the left use ardent Trump supporters and alt right people as synonyms, which is not entirely accurate. In truth it's more that the republican party base has shifted so far to the right that even those that do not share the alt right ideology or methods are willing to accept their new alt right overlords.
So the current Alt-Right is basically an invention of the media who failed to smear moderate conservatives. Slobbering morons.
with what is actually true. The truth doesn't necessarily fit with your worldview. This :
They originally state that it was coined by a Neo-Nazi then go on to say it means "not mainstream conservative."
is true if you put some limit as to what "not mainstream" means. Some horrible person invented the term, then some slightly less horrible people used it to brand themselves and a few others. Then they tried to build up a coalition of non-mainstream right wingers under that flag. Many people on the left tried to warn everyone that it was dangerous, and so did some "centrists" but the right didn't listen and became mostly united behind Trump and the alt right. Because Trump is the leader of the alt right (or at least someone very close to the alt right who is pushing some of their agenda), people on the left use ardent Trump supporters and alt right people as synonyms, which is not entirely accurate. In truth it's more that the republican party base has shifted so far to the right that even those that do not share the alt right ideology or methods are willing to accept their new alt right overlords.