Not reading your history is a common failing of the ignorant. In fact, women in this country had an incredible sense of modesty (often criticized by the Hugh Hefner's of our land) from the earliest days of our Republic right up until the 1920's. This may explain why sexual assault was virtually unheard of, and why (in public at least) women were treated with a seemingly exaggerated courtesy and respect, right up until the the middle of the 20th Century.
Sexual assault was virtually unheard of because the victim, up until recently, would be too ashamed to report the assault and many police departments would not bother investigating the crime if they concluded that the victim was "asking for it."
The Muslim world enforces very high standards of modesty for women. Do you think sexual assaults don't happen there?