Another point that I've discussed with Kathy is that a good number of women come to firearms training because of some unpleasant abusive or criminal incident in their life. In discussion beyond the male oriented stopping power and equipment focus, these life incidents may be better discussed in a female group.
Male participants may not understand such issues, be prone to announce rape myths, give insensitive insights into abusive situations or the like. I know this kind of thing from my professional life.
If you take a male mainly class, you find guys who don't want to hear the avoidance, legal risk, negative psychological outcomes of lethal incident reports. They would rather posture about equipment and when they can shoot someone. Such talk would probably short circuit women's concerns about lethal force use and its consequence. If you talk to trainers (male and female) or take classes, you know these guys. I've seen Vicki Farnam discuss teaching women and darn it - some guy had a hissy fit that women didn't like the compact 1911 that HE thought was best. Vicki shut him up.