I don't think it's an attempt at correcting neo-nazis, but rather indirectly says that they only seem to use it as a signal: they don't care about (proper) use at all, just want to associate themselves with a (glorious?) past through marketing.

> Oh yes, let's grammar-nazi the nazis.

Using wrong letters and ligatures (in Fraktur) has barely anything to do with grammar; this is rather orthography.