Yeah, this really shouldn’t be a case people who support abortion rights should stand behind, but I think the focus is on how their chat history might have been compromised, although I´m not sure what people were expecting on that end either. The fediverse will also eventually have to deal with requests from law enforcement as well, too.
If you private message someone else on a web service, your entire conversation is saved on their servers. If you have an app on your phone, then it can be designed to store the messages locally.
The reason the investigation was started wasn’t because someone peaked in on it, it was because there was a buried dead baby.