I don't think people turn a blind eye to it so much as people realize that every call did not go one team's way. Terrence Williams got pushed in the back on a bomb, no call. Dallas' punter go touched a lot harder than Detroit's did and there was no call. It all kind of shakes out in the end because there is so much ambiguity to it.
Sure Detroit MIGHT have benefited from a PI call but then again, Stafford MIGHT have thrown a pick 6 on the very next play. If Dallas gets that PI call for the bump in the back on Williams, they might have thrown a TD to Dez or Witten after than. If they get the running into the kicker call, they might have drove down and scored a TD.
Nobody knows what would have happened. Any change in the game MIGHT have benefited Detroit enough to win. But the game went how it went. It's over and no amount over arguing is going to change that.
What made it controversial is that the flag was thrown and the penalty was announced and then it was negated without explanation (and also that Dez Bryant ran onto the field with his helmet off to yell at the refs in the interim). It was a very unusual sequence of events. I'm not sure why people keep ignoring that in the discussion and talking about it as if it was a run of the mill blown call. As you say, blown calls happen all the time and they generally even out over time. This was not that. This was a correct call that was subsequently reversed and became a blown call quite a while after the actual play took place. It was very, very unusual.
Also, Detroit WOULD have benefited from the PI call (or a defensive holding call). There's no "might" about it. Yes, subsequent events might not have gone their way, but that doesn't make it a question. Would you say that a team "might" benefit from a pick-six because the other team could conceivably score five touchdowns in a row after that? No, of course not. If a play makes a team more likely to win, they benefit from the play. Detroit would have benefited significantly from the call standing. I think the reversal shifted their win expectancy something like 15% according to models.