what does "Nietzsche is Pietzsche" means
The one who says that is a fan of Nietzsche.
Phonetically: Neetchee is peachee
It's a play on words- Nietzsche rhymes with "peachy". When you say something is peachy, you mean it's just fine from your perspective.
So, you're basically saying "I like Nietzsche"
i think that Replace is right. It might be referring to the fact that Nietzsche was less than 'peachy'. He was a philosophical, serious guy who believed in life-affirmation, which i think is just questioning the truth of life, no matter what social standards propose. It's sort of a joke, comparing two things which are actually contrasts.
that which does not kill me makes me stronger