They were just uploaded this way, it's very odd. You can tell that it's compromised the art a little bit here and there. The thing is, the screen tones are wholly intact. So it's not like it was just a resampling error at the very end. Again, a few SFX in the earlier pages are also without anti-aliasing. So it was something that happened halfway through putting together the pages.
Notably, however, the white stroke that the author uses on text was anti-aliased while the text itself was not. A raster image program like CSP or PS can't do strokes without anti-aliasing, while text layers themselves can be. This led to a few pixels here and there around text being grey, while the rest of the pages where entirely binary on pure black or pure white.
To me, my running theory was that, somehow, after doing the linework but before doing the screen toning and text layers, the author managed to irreversibly remove all anti-aliasing from the art. This can be done by resizing with the wrong resampling method. Feels like an error in the process and, rather than redoing parts of it, they just ran with it. I could very well be wrong, but that's what I think.
Everything is back to normal next chapter, though.