The example above of a 2-pair hand crumbling around you makes sense in its own context, but a) it's not likely to happen and b) betting hard on the flop (to little strength) is absolutely the right approach and will take down the majority of pots there and then. Even on the turn, the same is possible. And none of A2, A5 and A& (hands which are likely to stay in) will beat you.

So to all intents and purposes, all its saying is "if the board turns against you when you have a decent but not great hand, fold". Well, we knew that already.