Its dog whistle. Swastikas are a thing of the past, the modern strategy has changed. Now you show your far right fascist identity by using a symbol or term that seems perfectly normal, but carries loaded meaning for those in the know.
The far right understand and can share a crypto-salute that way.
The centrists have no idea and look right past it.
The far left know and call it out, and the far right can allow the centrists to call the leftists crazy for making a big deal and calling an otherwise innocuous statement or symbol racist or fascist, so then the centrists brand the left as looney and end up sympathizing with ring wing radicals.
Its the same as Pepe, the OK hand symbol, the Kekkistan flag, putting parentheses around words associated with their conspiracy theories of Jewish world domination, and of course, sub to Pewdiepie.
Why that you tuber in particular? Simple, because hes become associated with racist dog whistles and outright racist speech that triggers the libs. Doesnt matter if Pewdiepie himself wants that label, but his brand was sympathetic enough to the right wing 4chan troll gamer identity that they chose it.
^ This.
A lot of it is indeed the alt right being dishonest with their intentions in order to gaslight the left and continue to communicate with others of similar mindsets. ---