I guess what happened was before he was in the NFL, so the NFL as an organization can't punish him. I wouldn't have drafted him if it was me.
Like SV, I try to be careful about how I judge DV incidents as reported in the media. Back in my younger days watching my dad beat the **** out of my mom and I, we couldn't even get the cops to show up. These days, they show up because people heard yelling. The man is 90% sure to be considered at fault regardless of what happened.
In general, I think you should avoid hitting a woman, regardless of her behavior. The obvious caveat, is if you think your life or physical well being are in danger. Woman slaps me, I don't hit her. Comes at me with a knife, she is in trouble. Even in the second incident, I expect I'd have to prove my side of the story while hers would be taken at face value.
OTOH, how egregious does it have to be for someone to not want him on the team? Hitting a pregnant woman in the stomach and choking her seems a pretty bright line, to me. Ray Rice's clocking the woman, knocking her out (did he drag her out of the elevator) seems to be a pretty easy line to draw.
What if he just slaps her, with open hand? No bruises, nothing. Anyone can get pissed off and do something stupid. If no one gets hurt, was it a one time thing or a pattern?
What if the charges are dropped and/or not dropped, but there is no conviction?
I think the NFL goes with whatever the flow of the media hype of the story is rather than based upon the facts at hand and that is ****** up.