Now that we've spent all day trying to confirm that Carlos Ruiz's goal should have counted, let's take a look at an opposite view.
Commenter Oreland827 passed along this video that was shot from the stands across the field from the angle the TV cameras had. Jump to the 3:12 mark:
In real time, the scene is pretty chaotic. It's certainly not easy for the linesman to make a decision with so many players moving forward and backwards right in his line of sight.
On top of that, the linesman has to be looking at the ball striker and the receiving players at the same time. That's just about impossible in a situation like this.
(Yes, I know better than to tell you to be nice to referees. I certainly have my fair share of issues with the officiating in MLS. But a situation like this can be hard to get right for even the best linesmen in the world.)
So let's go back to my thrift-store quality telestrator. It may not be the fancy equipment they use on television, but I don't have a television network's equipment budget (or salary budget, for that matter).
Danny Mwanga, Carlos Ruiz and Sebastien Le Toux are all onside. Sheanon Williams is offside, but out of the play, so he doesn't count.
And Jack McInerney is... well, it depends on how much daylight you can fit between his big toe and the defender's right heel.
It looks to me like McInerney was offside. Just to be sure, I spent a couple of extra pennies to get a second color of cyber-paint for my edition of Photoshop. The result was this:
That makes it look pretty obvious. Unlike Williams, McInerney was very much involved in the play. McInerney was right next to the defender who deflected Miglioranzi's shot, and he was also right in the goalkeeper's line of sight. The latter factor is especially important in FIFA's explanation of the offside law.
So the linesman would have been within his rights to raise his flag.
A call like that that almost never gets made, because McInerney literally went from being offside to being onside in the time it took the linesman to turn his head to the 18-yard box.
In the end, the only people whose opinions actually matter are the linesman and the referee. They said it was a goal, so it was a goal. But I figured this angle was worth a good look, and some discussion.