In a venn diagram of neo-nazi's and alt-right, I'm sure there would be plenty of overlap, if not neo-nazi's being a subset of the alt-right. But to categorize the entirety of alt-right as neo-nazis is itself not useful, as you can then not have a conversation about the actual viewpoints of the alt-right.
I'm really disappointed in the quality of the discourse on both sides this election cycle. Straw men abound.