Well you'll have to apprise of what "top of the thread" means because I can't find one.

I can't think of anyone in my circle of friends who would consider the use of "bitches" in that joke to be appropriate, and we are a jolly lot. It's a derogatory way of referring to women, and the women implied in that joke seem to have done nothing to deserve it unless you think there's something wrong with tampon-wearing.