Is it true? No? Then it's a defamitory assertion made in a public arena. Might make people stop and imagine what damage could be done to their own lives with unfounded allegations for all the world to see. Look up the Daily Mail's track record on being sued for similar.
Yeah, but the tort laws and tradition are different in the US. UK defamation cases much easier (why people try to get their cases heard there.) Interestingly we even upped the ante with the SPEECH Act, signed into law 2010 saying that cases in other countries, looking at the UK in particular, in which damages have been awarded might be unenforceable here. It will be interesting to see how various agreements in the works, TPP and the like, deal with this.