He addressed that in the article: Pillow is cross-platform and cross-architecture, so these sorts of specific optimisations (x86-64 only, with some pretty speci

He addressed that in the article: Pillow is cross-platform and cross-architecture, so these sorts of specific optimisations (x86-64 only, with some pretty specific instruction requirements) meant that the author felt it wouldn't be a good fit in the original library