Because V2 can be limited by the higher of 1.1 VMCA or 1.13VSR, if flaps are extended 1.13VSR is lower and therefore the 1.1VMCA limit is more likely to be controlling.
Its interesting to note that V2MIN must also not be less than VR plus a speed increment attained before reaching 35ft. When the aircraft is very light and accelerating quickly this can cause higher values of V2MIN at the left hand side of the graph. I've left it out here for clarity.