It would be natural to think that men like to render women, and women might like to render men. In that case, women buys more clothing than men, that's a fact, but if women render men, then they would also be buying more male clothing - but I don't see that happening, and I am talking about the other stores I have worked with in the past decade - not just HW. This is a market that self-regulates by offer and demand. If there were a solid demand for male clothing, vendors would be making more of them, and better ones. But as we know, that's not the case, and that's why we are having this conversation.
As mentioned above, I have discussed this for years with female artists from all medias at DeviantArt, asking them WHY most of them like to render or draw other women. The answers varied between "I don't know how to draw men" and "I prefer to depict female characters".
I am male, and I like to depict beautiful females. I have been doing this for ages, which means I have specialized in dressing and posing women. The weird part is that whenever I have tried to depict male characters, I can't seem to understand how to pose them properly, because I had zero experience with that - AND I AM MALE! LOL
In my attempts, men look helplessly gay - as noted by my wife. All the intricacies and subtle nuances of female posing I have learned through the years end up transferring to my male poses, which is BAD. The thing about attractive men is in the eyes of women, and I will never truly understand that part as I do for female characters. Add to this that there is nothing on a man that I can possibly find attractive, and therefore is not fun for me to work with. You can say that I have a genetic disposition to have a passion to depict women. That feeling is absent when working with male characters.
Coming from there, if most vendors are male, chances are they would be more inclined to do female contents as well.
And if we look at the historical and geopolitical side of events, women was always "protected" by society, while men was made disposable. We have hundreds of years of that kind of mentality, which we can still witness on everyday TV nowadays - nobody can touch a woman, but men can be beaten senseless to death by the dozens. If a woman kills a lot of men in a movie, she's a heroine. If a man kills a lot of women in a movie, he's a serial killer. Some of the most famous studios in the world, like Disney and Ghibli chose to make most of their protagonists female, because they create more empathy with the public. In other words, there would be a bigger chance people wouldn't care what happens to them if they were male. For whatever reason, we have been conditioned to care more for women than we do for men.
We can see this dis-balance in social events, where each individual woman wears a unique garment, while all the men are dressed exactly the same. Not only that, but it's considered a social offense if 2 women would happen to come with the same outfit - they would be mad. It seems like it's a social rule that nobody cares for men, and that reflects in this market as well.