I don’t grok it either, but it seems to mean far right. Compartmentalize much, don’t they? I got a label for them, but it’s not suitable for polite company, if there’s even such a thing left these days...
I’m not sure, but I think the Alt-right is younger people, with a more in-your-face style. So some 20-something guy posting news and witty things with a few F-bombs thrown in for good measure.
I’m not sure if that Milo guy is “alt-right” - but that’s what I think of.
I know my kids like some of them.