Yeah, really ridiculous, and just Goodell throwing Peterson under the bus because he's gunshy about public criticism right now.
The NFLPA and NFL needs to have a formal policy in place, and they need to either rely on the legal system or not. This incredibly reactionary, decide-as-go approach is just at total mess.
I think the ideal solution is to rely on the legal system in adjudicating punishments, and leave it up to individual teams to decide to weather the storm of public condemnation or not in deciding to suspend players based on extra-legal circumstances or TBD legal circumstances. The league stepping just creates all kinds of problems. I understand why they want that control, but it should be done at the team level.
TBH though, my interpretation of this is also colored by some pretty strong beliefs about this incident and the handling of it that would probably be more appropriate in the shack.