I agree with vM. The answer is slightly unsatisfying, however, because the rules for Human Waves allow the Attacker to remain a HW Unit (and continue moving) once the dummies have been removed:
A25.234 ENDING THE HUMAN WAVE: A unit remains a HW Unit (even if no longer adjacent to another HW Unit) until it is: eliminated; broken; out of MF at the end of an Impulse; at the start of an Impulse in a Location (or in a hex with a pillbox) containing an armed, Known enemy unit [EXC: if it uses the Impulse to move beneath an enemy-occupied Entrenchment counter]; or is a Guard due to capturing a SMC/Unarmed/Disrupted unit (25.233).
So if a HW unit uses an impulse to move into a Location with dummies, the dummies get removed so that the Attacker will begin the next impulse still free from rule A25.234.
This should then apply to a DC Hero except that the rules don't seem to allow such heroes to EVER change from their initially Designated Target. Though it is not explicitly stated that they can never change targets, it is also never stated that they can. vMarwitz's citation reinforces this idea. An T-H/DC Hero only gets one Designated Target.
P.S. This problem doesn't seem to exist for T-H heroes, since the RB states that these must designate
an AFV as their Designated Target (is a 5/8" concealment counter "an AFV"? I wouldn't think so. It is just "a unit.") For DC heros, any enemy "unit" will do - which includes a stack of dummies.