I know the "swastika sword" is old news by now, but I did have a realization about it. When you think about it, there's no swastika more authentically Nazi-esque than one made by culturally appropriating the manji and transforming it into a swastika in order to attack Jews.
The swastika was originally created by Nazis taking the image of the manji and recontextualizing it as a symbol in their crusade against Jewish people, deliberately distorting its original meaning. Very similarly, Ian & Hasan took the image of the manji and recontextualized as a symbol in his crusade against a Jewish person, distorting its original meaning as a sword from the anime Bleach.
If anything, you could argue Ian & Hasan took the extra steps necessary to assuredly make it NOT a manji in that context, but, as Hitler had done himself, wholly converted it into the swastika. They even angle it like a swastika in the photo. Their cope that "it used to be a manji!" actually further indicts them and their decision to use it.
tl;dr: Ian & Hasan are actually doing more to emulate Hitler by converting a manji into a swastika in their crusade instead of jumping straight to a swastika.