The wall is a red herring. The plane landed halfway down the runway at high speed. Something bad is going to happen if you do that at any runway on earth. In SFO you'll end up in the bay or hit the terminal depending on the orientation. In Toronto you'll crash into a highway. Stop looking at the wall and look at the minutes before the crash.
Occam's razor: the wall is most probably the cause of the unnecessary explosion that killed 179 people. The airport built ILS, or localizer, on unnecessarily over-engineered concrete structure where there shouldn't have been any obstruction. The ILS are supposed to be built on level surface or "frangile" structure so they can be easily destroyed when there is an overrun. There are reportedly at least 4 other airports…
Where did the idea of fortifying Localizer (LOC) come from, was there prior art specifying any degree of fortification (or lack) ? Perhaps these kind of radar (adjacent) installations are traditionally fortified, like maybe the civil air services were influenced from militry air services were things tend to be overengineered?
Perhaps saving the LOC is more important than saving a single aircraft? Some idea like this piece of infrastructure being more important that any single aircraft's safety?
The point is we might not see the reason why fortifying the LOC was obvious or straight forward to the Korean engineers.
Also, I've seen no credible evidence to support the idea the LOC is supposed to be built on a level surface, or built in a destructable way. Addressing the first point, the LOC makes sense to be slightly elevated given how they operate with near field low power radio waves. That said, these kind of slightly elevated instrument might not require an earthen mound, sourounded by concreate walls. Which goes to the second point, I can think of reasons to have these kind of LOC runways homing antenas destructable, and I can see them being robustly durrable. This thing was way past the end of the runway, and as unpo0pular as it might seems... it's a very bad thing to run out of runway. Somebody else wrote that some airports have a lack of open field beyond the end of the runway, and so it's a persuasive argument stuff could be built out there.