Why worship Shiva Linga?

I always wonder WHY hindu society worship Shiva Linga in the Yoni instead of Shiva statue. This was always my great concern because in all the temples usually I see worshipping gods/goddesses statue but in the case of Shiva "Mahadev" I noticed that everywhere Shiva "Linga (Penis)" in the Parvati Yoni (Vulva). Today I got the satisfying answer from the book titled "The origins of EVIL in Hindu Mythology" Wendy Doniger O'Flaherty published in 1976 by to address my concern.

One of the Nepalese, Mr Bashu Dev Lohani said "The linga is represented with the yoni, a symbol of the goddess or of Shakti, female creative energy.The union of linga and yoni represents the indivisible two-in-oneness of male and female, the passive space and active time from which all life originates."

I was shocked seeing the figures that in a day there are 66 rapes in India. Gosh! Couldn't even imagine in such a religious country, where woman ahs worship as a goddess can have that many crimes.

Reference

1. Wendy Doniger O'Flaherty. 1976. The Origins of EVIL in Hindu Mythology, The University of California Press, California accessed from http://books.google.co.in/books?id=Ug_9cVR4lW8C&pg=PA275&lpg=PA275&dq=incest+in+hinduism&source=bl&ots=mHC5RoMT0v&sig=cCoWr1iEhGr0nZzFHuRuqhO_LTc&hl=en&sa=X&ei=ND_lUOHoFcXXrQfhv4G4Cg&ved=0CDkQ6AEwAjiCAQ#v=onepage&q=incest%20in%20hinduism&f=true