Graf threatened to sue Ethan Ralph, because Ralph called him a pedophile and said he runs a site for pedophiles. But because Ralph is in the USA, where free speech protections are pretty strong, it’s questionable whether it actually qualifies as defamation or not. IANAL (I Am Not A Lawyer), but I have read some 1A law to understand prior cases.

As far as I’m aware, the basis Ralph would have for making that claim is that poa.st allows (or allowed in the past, I don’t keep track of their rules) people to post lolicon. And frankly, on that basis alone I think he has a valid defense to a defamation claim, since a reasonable person could conceivably believe that anyone interested in lolicon is a pedophile.

I think it would come down to whether graf qualifies as a limited purpose public figure or not (I believe he might, since he has had interactions with the press and runs a rather infamous website). If he did, then Ralph’s statements would need to meet an “actual malice” standard to qualify as defamatory. Meaning not only were the statements false, but Ralph knew they were false when he made them, and had no rational basis to makes those claims. Merely allowing lolicon would probably be a sufficient basis under the “actual malice” standard, so graf would lose.

And there are a number of other defenses here, such as whether the statement qualifies as opinion, or rhetorical hyperbole, but I don’t know enough to go very deep on the analysis. Again, IANAL. Maybe @Humpleupagus can weigh in with some better analysis. But bottom line is I think it’s unlikely graf could win, unless I’m wrong and he actually does qualify as a private figure.