Fairly simple, the algorithm obeys by some *validated* rules, we humans don't.
The same sector 'flaw' is, i suppose, a necessary evil for the parser calculations once it gets to distribute the maximum space to the relative values set forth by the options (rare, abundant, etc) selected. The principle is the same for Stars neighboring seven parsecs gap or even, the three tiles minimums between any planets - for another good reason i guess; 1) effective pathways (btw, code *must* find straight routes and evaluate obstacles!) for traveling ships and, 2) many more unforeseen effects.
Which is exactly why i'd NEED a true 3D galaxy map... with at least three layers, above_middle_below! In
my Milky-Way anyway, Polaris is waaaaayy above the local giant Sun and the Crab nebula is in fact almost entirely below Earth's ecliptic.