Why ask why...
Is this surprising at all?
The culture these immigrants come from assume a woman on the street dressed (as they deem immodestly) is fair game for verbal abuse or worse (Taharrush). This sort of abuse was being reported before the recent Cologne New Years Eve events.
No Groping Pamphlets for Syrian and North African migrants in Germany
While many feminist (Amanda Marcotte as an example) are silent on the surge of rapes, gropings and
harassment of women in Europe because their hypocrisy and their leftist politics coming first, some feminists are finally speaking out. The police, however, are more concerned cracking down on citizen anti rape groups.
EBL: Merkel and Germany reap what they sowed and European Street Fashions Were Fun While They Lasted
DaTechGuy: In Germany they blame the victim
Camp of the Saints: Taharrush
NRO: Merkel's Germany