Nedem Onuorah did a really good bit about this and how the players who were in the game 20 years ago really don't get it when they commentate, especially when teams make a mistake and they come out with "why are they doing that/they're not good enough/it's too dangerous". His point essentially is that the players and coaches know exactly why they're doing it, the point is to stretch play, draw the opponents in and make space in the areas behind them. The coaches know there will be mistakes but that's part of the improvement process & the testament is actually how few goals are being conceded now when doing it. The issue last night wasn't the system, it was simply a mistake by Beadle, who should have kicked it first time. He'll learn from it.
The point though, about these pundits, not quite appreciating how the game has changed tactically is a sound one, i can't imagine that Carragher would have got many games in a side that played in this way. It's probably time for a bit of a changing of the guard at Sky etc.