This is highly overlooked “The company tried to subpoena Google using the DMCA but the chosen mechanism only allowed Bungie to identify an alleged copyright infringer, not the sender of allegedly abusive DMCA notices.”

We have been the recipient of many invalid notices to Google. Google publishes the details via Lumen but makes it impossible to reasonably analyze the data. 1) They hide the sender info. 2) They make you validate, via email, for EACH DMCA you want to view. In other words, they claim transparency, but practical use isn't possible. They also don’t publish DMCA’s against sites like YouTube.