I think this was related to their plan before, in the case that got decided (specifically that Reddit didn't have to reveal the IP addies of its clients), but that's always been a problem especially if an ip address leads to a router or is dynamic at the ISP, then there's no certainty it can be identified with a single person.

This is how the whole twelve-strikes program was formed where big name ISPs would (hypothetically) give demerits and eventually throttle or disconnect ISP addies that were identified as engaging in infringing activity. The problem is, clients stopped wanting to pay their bills when quality deteriorated, so it's not consistently enforced. In fact, companies that are not Comcast or Xfinity are motivated not to do anything beyond threats.

ETA: Similarly, it's actually to the benefit of social media websites to preserve the privacy of their clients, since incidents in which they cooperate with law enforcement reduces engagement. Google used to have a robust legal resistance to giving away personal data. It was deteriorated through enshittification, but now Google has lost enough reputation that it's looking for ways to preserve privacy, like the new effort to constrain personal map data to devices, so Google is unable to respond to location dragnet warrants. They're still in trouble for search-term warrants.

(Note the map thing is not yet rolled out, so don't use Google maps when burying your bodies.)