Spot on, Danny. I too was befuddled by the notion that anyone would try to land a perfectly good airplane under those circumstances. No doubt some of that is a function of culture (Southwest's emphasis on OTP), and some of it may end up being that they were influenced by the success of the preceding flights whose pilots got lucky and made it in.
As is typical in accident investigation reports, the investigators will no doubt look for ways to address the causal factors through changes to the regulations. It will be very interesting to see how the final report addresses the legalities involved in this case. I wonder if they will require similar "buffering" to be applied to actual landings on contaminated runways as many regulators do when flight planning is done.