Osmo you say it as a joke but there is an explanation. On forums / message boards (1) the identity of the defamed must be known and (2) the person doing the defamation must be someone a reasonable person would believe. So on the latter point, if you are someone who no one respects or someone who often posts crazy conspiracy theories you can more or less say what you like and won't get sued for defamation. Don, fortunately, fits neither of those categories (but if he continues to claim Gowling was excellent I might change my view - Gowling put Tenor on notice that shareholders were no longer going to be placid, poking the bear tends to result in being bitten or worse).