Before we can understand why nobody is posting for the male gender, we need to think about what boys would gain from Pinterest. The dorm room hacks are usually feminine, but the general idea can be repeated in different designs. Boys might also use Pinterest for tattoo ideas. If they are into fashion or need help refining their look, they can use Pinterest to see visuals of outfits. Last, the most common thing boys use Pinterest for is to get ideas for what their significant other wants.
There is a definite stigma around males who use Pinterest and it is something that needs to change. I also think, Pinterest could try to appeal to males more by pinning things that they would be interesting in pinning. So to all the boys out there: if you start creating pins for the male environment, you might be surprised with the response and growth of your page. It would also be cool to say you increased a community on a social media platform.