In general they seem to have gone for a "just draw slices of the city" approach, which I would normally fault them for, but AFAIK a lot of Rome's suburban structure genuinely worked like that at the time. Of course, the absolutely massive post-war growth (IIRC, in 1948 Rome was only just barely the largest city in Italy) messed with that, but you could say that about any number of these boundaries really. And yet they stayed unchanged until 1992 everywhere but Friuli.
Considering that they determined the election of one or two people in each election, I suppose they thought it didn't really matter.