Why are women sometimes referred to as "broads"?

This as accurate as I've seen.

"Pre WW II slang for an independent, assertive/aggressive woman. Usually in show business, a broad is a singer, dancer, actor or business-woman who sings loud, parties hard and is often abrasive, sarcastic and in-your-face. A variation is the "classy broad" which implies she has either been born rich, snagged herself a sugar-daddy, or has succeeded on her own.

Broads are generally moderately attractive or better, are never seen without their best dresses and perfect makeup, and know how to compete and win in a man's world. In some pre-war Hollywood films, broads are portrayed as gangsters' girlfriends or even their accomplices or gun molls but that was rarely the case in real life. Also in Hollywood films of the era, broads chewed gum incessantly and spoke with a thick, sarcastic New York accent.

Often men who felt threatened by strong-willed, successful women would call them broads in a derogatory sense.

Bette Midler on her persona: "People always love a broad -- someone with a sense of humor, someone with a fairly wicked tongue, someone who can belt out a song, someone who takes no guff. "

Hey Manny! Lookit dat broad... She's built like a brick shithouse! - Construction worker to a friend.

by Aleksei Kotsov January 31, 2014"