As a Hubski user, I'm personally resistant to porn on Hubski for three simple reasons. 1) Hubski is a great entertainment site without that stuff propping it up. I don't need other people to share porn with me. Not here, not Reddit, not anywhere else. If I wanna see it, I know where to find it. 2) Hubski is a small site, and believe it or not, sharing port is a huge legal liability. mk and co. would probably rather do without the extra responsibility and worry that comes with such behavior. 3) Sharing porn and discussing it with others is flat out weird, creepy, and gross. This site is too good to have to carry that stigma.
These are good reasons to explain why we don't currently have to deal with porn on hubski. Because of the current norms against pornography, new users will adopt the mindset you've described here. But, eventually we will get people who just don't care, or who care specifically to bother people with porn. Fortunately, for the reasons I outlined, I believe hubski is structurally more resistant to those kind of people ever getting a foothold or following. There's more friction since you'd have to make a second account to hide your porn habits.