What bothers me about this is that I'm 99.9% sure if there were a website dedicated to archiving and collecting the manifestos and/or other documents/content created by spree killers/mass killers no one would care.
For example. Randy Stair published hours and hours of video, writing, and other pieces of media detailing his plans, his worldview, and ultimately his crimes. I don't know if anyone's put a FOIA out on the security camera footage, or if that would even be possible, but even his killings were documented by the store security cameras.
Similarly for Columbine, for the Vegas shooting, for Stoneman Douglas, the Brevik massacre, Christchurch shooting, etc etc etc. These people publish their worldviews and they may be twisted, sick or otherwise insane; suppressing the information or trying to prevent people from reading the words of insane people who have committed crimes of that nature only makes me think there's something in the manifesto that the Slovakian government doesn't want me to see.
God forbid the day ever comes and someone publishes a manifesto to this site; I'd delete it and hand a copy over to the authorities but once the investigation was over and a trial started/the shooter died in his rampage I'd see no problem hosting it because there's no reason to withhold the demented thoughts of lunatics from people interested in looking at them.
That's all just my opinion. Josh is fat and retarded, but he should be allowed to host a PDF full of deranged ramblings from madmen without issues. He didn't write it. He probably doesn't endorse it. It's just information.