A website was bullied off the internet because it showcased the horrible activities of horrible people. I'm far more concerned that a handful of Twitter users can memoryhole an entire community.
Having the power to shut that place and therefore behavior down but choosing not to means they were complicit. Deplatforming works, the influx of new bullies shrinks when you make their place less public.
Therefore it would seem that this particular removal is motivated by erasing the documentation and performing a cover up.