It looks like all the Marks on your view (on both axes)
has the very same location -- Target Lat / Target Long.
So each and every Mark label has the exact same place on a map.
They're stacked on top of each other over the Target Lat / Long crossing.
And there is no way to place them at the arbitrary location on a map.
So taking into account current design and pill arrangement
there are other ways of getting closer to the desired picture.
One could play with color transparency of filled zip areas (say 50% or less),
and use a Dark Map option to increase a contrast of boudaries and labels.
Hope this may help.