I blame missions for giving people such low armor ratings.
Well, really, it
is realistic. The heaviest armor I've seen in the books that you can wear "casually" without gimicky layering, supplementary protection and tailored gear (i.e. FormFit, PPP and Softweave

) is something like 7/7 for Steampunk or 8/6 for an Armor Jacket.
I really doubt most of the Gangers and thugs you deal with in Missions aren't going to be on the same level of Adequately Cautious (like paranoia, but they really
are out to get you) as a Runner when thinking about their apparel... assuming they can even afford that stuff.
EDIT: Corrected "...are going to be..." to "...aren't going to be...". Very, very important difference there.