I actually don't have a problem with how the NFL is playing this out, even considering the agreement between NFL/NFLPA/Vikings. JMHO, people are completely ignoring the final sentence of the NFLPAs own description of the agreement:
“The player agrees that, effective as of yesterday (September 17, 2014), he is placed on the Commissioner-Exempt list with full pay until the criminal charges currently pending against him are adjudicated. No discipline will be processed or imposed against the player, by the Club or the League, until after the pending criminal charges are adjudicated.”
So, the league has promised not to "process" discipline until after the legal resolution, which is exactly what it is doing.
After the Ray Rice debacle, the NFL and Ravens were rightfully pummeled for not even attempting to get a tape that existed, and then it wound up on TMZ. Consequently, the NFL is (wisely I'd say) trying to get the facts that would otherwise have become public at trial, and could certainly become public, which makes sense. The NFL undoubtedly expects to be denied access to the AP evidence, but last thing the NFL needs is to decide not to punish AP based on assumption it won't have access, and then lo and behold 'unavailable' new photos are released by TMZ. Then the NFL is crucified for, not once but twice in the same season, failure to use all efforts possible to seek evidence. If they are denied the info legally, they have cover. Just as they'd have had cover if they had better proof of demand and denial of that Rice video.
Any event, to read the NFL/NFLPA/Viking agreement and conclude the NFL had to act immediately after this case was settled behind closed doors with sealed records is not logical. It's plainly agreed the NFL could not begin processing possible discipline until the legalities were adjudicated, and that is exactly what they are attempting now. That processing is complicated by limited access to the types of information the NFL should absolutely be considering, given the alleged/admitted abuse of a 4 year old child.