NFL, with Roger's help (he hired three people), adopted a policy of 6 game suspension by default for domestic violence after they blew the Ray Rice incident.
Giants kicker Josh Brown was in a bout with his ex-wife in which he was arrested. He just this month received a 1 game suspension after a hearing. If the default six game suspension was a starting point, the new policy wasn't explicit about it.
Seems like a discrepancy. The League issued a statement in which it failed to explain the discrepancy. Brown's wife and the police/authorities did not cooperate with the NFL investigation and it is unclear why. Its easy to imagine why his wife might not (payments, exposure, fear) but the official refusal is harder to parse.
It seems her injuries were minor and Brown doesn't seem to have been formally charged. But the League and the Giants successfully hid this for a year before results of his August 1st hearing broke. Odd that releasing contractural terms or CBA negotiations or conduct detrimental interviews always seem to leak, but they can keep a tight lid on domestic violence.
It was later revealed that Brown's wife had claimed to police that there had been 20 physical confrontations with her now ex-husband dating back to 2009.
Without police reports from those incidents or cooperation of the parties, it would be difficult without a complete investigation to flesh out and substantiate that claim. The NFL doesn't seem to have put one together for obvious reasons.
What the League is left with is a situation where like Greg Hardy, the player can buy off witnesses and the League is not obligated to more than polite asking for cooperation. What seemed to have changed after Hardy and Rice was that the default penalty would be substantially larger.
That doesn't seem to be the case. What does seem consistent, is that the League, if it can keep the details from public view, is still willing to side with the player.