Haha Trace, good luck on your sale, but I don't think this thread is screwing you, consider it a plug because you are a regular poster right? I'm sure you've got a fair price posted :)
And yes, you describe the situation accurately, I just don't think it's the best way we could be doing things, but in the end it is the way we do things. As you've pointed out in your argument, getting "screwed" is an entirely subjective way to describe a deal gone bad on GS. If we live in a world where people are content going about their daily lives calling each other "greedy scumbags" (my fault as Stephen pointed out) and "ignorant dipshits" then yes, you can't get "screwed" because it all rests on personal responsibility. But, if you have a problem with the idea of buying low on BPL, marking up, then reselling to other BPL members on the same forum (I do personally) and getting offended or annoyed when someone bargains in the way Justin did, and if you don't want BPL gear swap to turn into another Ebay, then I would argue you certainly can get "screwed". It's subjective.
I don't adhere to the idea that "the market will solve it" but that is just a reflection of my personal political bias and nothing more. I'm more interested in hearing people's perspectives on the issue because in the end while Greg and I might refuse to sell to a GS trader, I certainly don't expect others to do the same, and maybe somebody will say something that changes my perspective for the better. For example, at first I was feeling vitriolic when I heard Justin's account, but after reading some comments like Sumi's, I now agree that it was going too far to confront the guy, and I agree with you that ultimately the OP (and everyone on GS for that matter) has a choice to just move on. So thank you. But I'll say that a major reason why GS attracts me, and not Ebay, is the idea (albeit a potentially naive one as Katharina pointed out) that the BPL community (and thinking larger ultimately) could be a place where we don't take advantage of the "ignorant dipshits" out there because we can, but rather sell our gear at a fair price to someone who really wants and needs the gear because we buy and sell the gear to do what we are passionate about, getting outside.