What about the lessons that men could learn from women, and vice versa, in a well-run (no posturing allowed) coed shooting class?
There's certainly something to be lost if women are avoiding training because they fear posturing, or if they do attend but don't ask important questions for fear of ridicule. However, something is lost in unisex classes, too, precisely because the sexes are different... hearing different perspectives is lost.
Those perspectives may not matter if your goal is, like Jammer's, to teach students how to put rounds on target more effectively. A gun is a gun, accuracy is accuracy. While there are strength/carry-style differences on average, they are not categorical differences. More women than men carry a gun in a purse, but some don't (and some men utilize man-purse carry). Some women are stronger than some men, etc.
However, an approach like Pax's, with a class that is substantially about holistic self-defense and violence-avoidance philosophy, seems like it would benefit from different perspectives in a coed environment.
As a result, I wonder if the two views should be swapped. Jammer's courses, which do not seek to address differences between the sexes at all, shouldn't be impacted by alternating men-only and women-only sessions. Pax's courses, which are less narrow in scope, could potentially benefit more from mixed-gender classes, assuming the men weren't jackasses and the women felt like it was a respectful gender-neutral environment.
Perhaps reality is intruding, and while Jammer may wish that we all heeded the better angels of our nature all the time, Pax and other instructors realize that that's not going to happen for a while yet, and do the best they can, which in this case seems to be women-only classes.
“Compleχity is a symptom of confusion, not a cause.” —Jeff Hawkins
“The egg hatched...” “...the egg hatched... and a hundred baby spiders came out...”