Pittsburgh really has nothing to cry about. If they didn't want to rely on others, they should have taken care of business against some really crappy teams.
But I think Silver is reaching a bit here. Records don't tell the whole story since there are so few games in a season. Sure, the NFC wild card teams will have one or two extra wins, but they also got to play some really crappy teams. 3 of the worst 4 teams are definitely in the NFC (St. Louis, Detroit, TB, and you can add in KC from the AFC).
Meanwhile, 2 of the top 3 teams are definitely in the AFC (Indy and San Diego, with the Saints being #3). San Diego struggled early, while New Orleans is struggling late, but all 3 are the elite teams this season that are almost a guaranteed loss.
A team like Green Bay definitely benefitted from 2 freebies against Detroit. Give two gift division wins like that to these AFC teams and it's a different story altogether. Imagine Pittsburgh or Baltimore getting two gimmes instead of facing each other and Cincinnati twice. Green Bay also got to play St. Louis as well as Tampa, though they lost to Tampa. They also avoided the 3 elite teams this season.
Meanwhile, Pittsburgh and Baltimore both come from the AFC North, beat up on each other, and had to play San Diego as well, with Baltimore also having to play the Colts. I'd take either over half of the NFC playoff teams.
Houston and Jacksonville aren't very good, but neither was helped by having to play Indy twice this season. And unlike Green Bay, there were no gifts in this division that also included Tennessee.
The Jets and Dolphins both had to play the Colts and Saints. In division, they played each other, the Patriots twice, and even the Bills weren't an easy out. Denver didn't have much in the division, but they faced San Diego twice (beating them once), as well as the other 2 elite teams.
Which is all a very long way to say that I think the records don't tell the whole story. Every team has blemishes and games they could have/should have won. But some of these AFC teams that will miss the playoffs are still better than some of the NFC teams that clinched a while ago.