The case against Bolt began with a series of clearly defamatory claims against individuals, shown in the court decision to be false[1]. That’s never been part of the concept of free speech in Australian law, so, as far as the facts in this particular case are concerned, there is no problem. The main issues are whether it would have been more appropriate for the complainants to rely on ordinary defamation laws, and whether this case sets a precedent that might be used against legitimate expressions of opinion, for example on the appropriate criteria for determining indigenous status.
On the first issue, Mark Bahnisch (at LP, no link because of an annoying bug that stops me reaching the site from here) makes the point that the complainants wanted to address the attack on indigenous people in general embodied in Bolt’s piece, rather than simply the attack on their individual reputations. This is a strong argument. However, for cases of this kind, it might be better to change defamation laws to make racial attacks an aggravating factor, and evidence of malice, so that someone defamed because of their race could secure a judgement that made this clear, both in the findings and in the determination of damages. In particular, in a case like this, there should be no need to prove particular damage: the defamation should be sufficient for a judgement and damages.
As regards defamatory statements about a racial or religious group, of the general form “All/most Group X members display Bad Characteristic Y”, it would be possible to extend existing laws to allow class actions. That hasn’t been allowed in the past, but there is no good reason for a distinction between defaming someone as an individual and as a member of a group.
That would leave the case of statements that might “offend, insult or humiliate” members of some group without being defamatory in the ordinary sense of the term. While it’s easy to imagine some very troublesome cases, there are a number of defenses in relation to academic discussions, public interest matters and fair personal comment, and so far there isn’t significant evidence that the provisions have in fact worked to constrain free speech in any meaningful way. Still, if there are changes needed, this is the place to look.
fn1. In this context, the defence that Bolt honestly believed the claims to be true would be irrelevant. In any case, he obviously took so little care in his research that a defence of this kind would fail to meet the test of reasonable belief.