Missed this until a friend asked me to research it

Lexington Herald-Leader | 07/08/2004 | Women bikers group defends sign at parade

and I found it because of a blog devoted to motorcycle news.

This is one of those grey areas. 'Bitch' can be a pejorative or not. It, like many other 'four-letter' words can have different meanings, and this is especially true depending on the context. It's fine if you're talking female dogs or even using it as a verb. You start getting onto dangerous ground when using it to label a woman, though. For example, members of various groups (gays, blacks, etc.) call people within their communities words that would never be tolerated from someone outside the community. And whilst I understand the meaning and context from the point of view of the women on motorcycles, it was within a larger context of a parade with people from all walks of life, some of whom--especially children--would not understand the finer points of the label. I've marched many times for Fairness or gay-rights groups, for example, and I can't remember signs using 'fag' or 'dyke'. I certainly haven't seen black groups using the 'N' word, either, and I expect chaos would result, no matter what intent to 'own' the word for themselves there might have been. I don't see this as particularly different.