I think the soccer mom image comes from their lack of "sport" focused cars. I looked at their lineup and saw nothing that looked "aggressive" or "sporty". All of the cars looked pretty even keel middle of the road "nice".
[1] http://www.volvocars.com/us/cars/new-models/s60/s60-polestar
In my view, driving on public roadways should be maximally safe (and thus deeply boring); if you want to treat driving as a sport, then head to a track. Disclaimer: I own a Volvo :)
This may be my perception of that particular coming out of an old generation of looks, and catching up to the current one, though.