Localizing, what does this mean?
If it means determining the exact location for a sound, I can agree with you, if you are insinuating that most people can't determine the general direction, front back left right up down from their position, is utter non-sense.
Yes, it means determining the location (position) of the source of a sound.
It's a fact -- hardly nonsense -- that humans are easily fooled in determining the direction of a sound. In particular, it is quite common for a sharp sound like a gunshot to seem to come from the exact opposite direction than it really did. It depends on things like the exact position of your head at the moment the sound arrives.
Humans have two ears to help them to sense the direction of a sound. The brain compares the signals from the two ears and looks for several cues to determine direction:
One is the relative loudness in each ear; the ear toward the source tends to hear a louder sound.
Another is the frequency spectrum; the ear toward the source tends to hear a broader range of its frequencies, especially higher frequency sounds.
And a third is time of arrival; the ear toward the source hears the sound before the ear that's farther away.
Not all of these mechanisms are fully operative in the case of a sharp explosive sound like a gunshot. Time of arrival is probably the most important cue, but think about what happens when you're facing either directly toward or away from the source, or even if it's directly over you; in these cases the sound arrives at both ears simultaneously. You can't tell these directions apart. And that's why it's quite possible for a sound in front of you to seem like it's behind you, or vice versa.
But to point out what others have pointed out, in the context of the JFK assassination this is all totally moot because we have plenty of
other evidence that JFK was shot from behind and
only from behind, and we have plenty of independent evidence of the source and type of the shots: witnesses who saw the rifle in the window (and Oswald firing it), witnesses directly under it who heard the bolt being operated and the spent shells hitting the floor, and of course the discovery of the rifle on the 6th floor of the depository and the ironclad linking of it to Oswald as the purchaser and possessor.