From past articles, believe the initial reason for no refueling was safety oriented, inclusive of leaving the pits with the hose still attached, spills in the pits, etc. Forgot the exact number, but the GPM for F1 refueling was extremely high.
Carrying a full fuel load for the race but only the minimum needed to qualify was to add another variable in race strategy, same as starting on either the soft or hard tire compound, at least one set of each required during the race , believe for a F1 pit stop, there are 14 crew members, or use to be with refueling.
Summary of 2010 F1 Rule Changes
http://www.formula1.com/inside_f1/ru...ulations/8692/