Isn't white superiority partly about black lives being inferior or subhuman?
White nationalism isn't the same as white supremacy. It's often a blurred line. However, I am a firm supporter that Whites should be allowed to celebrate being the lead innovators of most of history. You can do that within good graces without being racist.
White nationalism may not be the same as white supremacy but when you tote about a symbol that was used in the Nazi party one would think that there is a belief that the person displaying that would have which is that there are always those inferior to them, or subhuman and this would give and encourage racist views.
It's no different than being apart of the conservative or democratic party but not endorsing all their ideals.