Linda,
I really think it's a bad idea to limit comments on the blog. I understand that it's been unpleasant, recently, but that's the dynamic of the web.
Your site has been interesting, to me, precisely because it's not the traditional "scientific" Bigfoot website. It's always been a bit quirky but that's the appeal. As I mentioned, it has never come across as a serious research site but there are already plenty of those. Regardless, how serious is website oriented towards an animal that does not officially exist?
Anyhow, my point is that if you limit commentary then you limit the "color" and appeal of your blog. As I advised, just put a disclaimer stating that you can't certify that any of the content is 100% true in that your readers pass along information, stories and opinions. Something along those lines.
Your mistake was not in sharing information or even promoting the information that was shared with you. Your mistake was in guaranteeing that the information was true. Other than that, everything was just fine.
Unless, you want to lose readership or investigate the authenticity of every last post; I would just post a disclaimer and proceed with business as usual.
There's plenty of room in the Bigfoot community for your site. Just play by the rules and you'll be just fine. Furthermore, you may continue getting a bunch of ugly commentary for a while but so what? It just brings in more readers. The comments will taper off as posters get bored with tormenting you; especially if you don't react.
Finally, I would not worry about the Steve Kulls guy. He's not nearly as funny as some of the other commentators and if I remember correctly, he was somehow involved with the Biscardi, frozen monkey thing. He claims he revealed the hoax but I think that initially, he was somehow mixed up in it. As an aside, what kind of grown man runs around wearing camo and a side arm; if he's not active military or police? Frankly, I'm not sure he even carries a gun. It may be something else in that thigh holster. Of course, that would make him even more ridiculous.
He's, by far, his biggest fan and a self promoter if I have ever seen one. I don't know the man but he just rubs me the wrong way. It's partly his appearance as well as his self appointed title of "squatch deputy" or whatever he calls himself.
Regardless, of the potential ugly commentary, open up the blog for posting. Freedom of speech is an all or nothing thing; know what I mean?
Carlos