Recently another one manga hosting site was downed by google personnel. The unofficial story is that their file hosting was located on google cloud servers and google nuked the content once it "found out" that it was used for "hosting illegal content".
Now some thoughts: Anime/manga community is, along gaming, is one of the latest bastions of cultural domains that didnt bend the knee to SJW bullshit completely. Could it be another agenda push by alphabet?
The upfront reason is DMCA, but at least for manga hosting sites that generate revenue from ads there's some contingency plan for that. This can be slightly deeper than it appears to be.