Why would autonomous vehicles be treated any differently then human operated vehicles?

The article unfortunately does not say what data is being required to be made public, but it does suggest that it is proprietary information, not specifically all information.

Crash information, I believe, is public information anyway. Perhaps not the intimate details of each crash, but the location, speed, etc, for both human and autonomous vehicles is (or should be) publicly available. There are definitely datasets for crash incidents, and there are rules regarding reporting of crashes in autonomous vehicles, which Cruise (I believe) failed to abide by and eventually led to GM shutting it down.

If the details were around the methods Tesla is using to assign robotaxis to certain areas and manage charge levels, should that be public knowledge if they have some special proprietary algorithms they feel are valuable?

The article says the information at issue is email communications, not trial results.

Regardless of where you stand, people need to know before they communicate whether their communications will be public. (It's already safe to say that people should understand any communications in furtherance of crime can be made public as part of prosecuting that crime - that even pierces Attorney-client privilege.)