My source of information on this is my regular commenter, DEEN, who has been following the Geert Wilders trial. See this thread.
It may seem odd that the prosecution is calling for acquittal, but even in the common law system of criminal justice, public officials such as prosecutors are there to help achieve a just outcome - it is not their job to secure a conviction at all costs. I don't know anything about the Dutch system, specifically, but I would guess that this applies even more in what I take to be a more inquisitorial process. DEEN or others can correct me or comment as they wish, but my guess is that the prosecutors in a case like this are more like a barrister appointed to assist the commissioners at a royal commission (i.e., "counsel assisting") than like, say, police prosecutors at a trial in a local criminal court in a common law country.
In any event, we now await the verdict in early November.
Though some people may think that Wilders is not a worthy person to be getting sympathetic attention, freedom of speech applies to everyone, and this case is an important test of how its boundaries will be regarded in those European jurisdictions that are very strong on legal discouragement of hate speech.
Let me be clear about another thing. I am a free speech advocate, but not a free speech absolutist. I do see a role for defamation law, though I think it should be framed quite narrowly. I also see a role for the state, in at least some circumstances, identifying a category of extreme hate propaganda and trying to prevent it. There may also be a cogent case to ban some kinds of pornography.
In all these cases, it's difficult to know where to draw the line, but that doesn't mean it can be drawn just anywhere. I'll set issues to do with pornography to one side, as they seem to be a bit different and they become emotional enough to derail a thread. That to one side, I don't think the concerns that justify some kind of defamation law simply scale up to the level of groups in society. Nor do concerns about hate speech necessarily scale down to the individual level.
If someone calls me a rat or a cockroach, perhaps repeatedly, it's insulting and as the social psychology research says it may certainly affect how people feel about me subconsciously. But it probably won't cause people who know me to shun me. It's not the kind of thing that defamation law usually addresses. It would be far more damaging if someone said, sounding credible, that I have Nazi connections or that I'm a pedophile, or that I once got away with committing a serious crime.
But imagine for the moment that we're living in the world of X-Men. Claims that mutants as a group have Nazi connections or practice pedophilia or commit crimes may be credible and damaging. Think of the blood libels against the Jews. But, depending on the circumstances they may just seem like incredible generalisations made by bigots. If I have some nice mutants living next door, maybe I'll be subconsciously influenced (think of the uneasiness that a lot of white people in the US feel around black people because of stereotypes that the latter are potentially violent). All the same, those of us dealing with mutants at work or in our neighborhoods are unlikely to shun them over these accusations, and they certainly won't shun each other. In many circumstances, where accusations are made against a large group, they are prima facie far less plausible and effective than when made against an individual.
These sorts of claims, by themselves, may be socially tolerable. And it's even possible that there may be a publc interest in airing them. Imagine mutant culture has developed in certain ways that are disturbing and merit public discussion (say a charismatic mutant leader has gathered a following who look on Homo sapiens with disdain; if this looks to be true, we'd better discuss it publicly, even at the risk of some commentators getting some of the facts wrong). Discussions of the alleged wrongs of mutant culture may turn out to be needed in a democratic society, and they may be less damaging than relentless campaigns simply depicting mutants as rats or cockroaches - though a successful campaign of hate will contain speech of both kinds.
The moral of the story is that if we're going to have laws that create exceptions to freedom of speech, we can't simply draw analogies, or scale up or down, from one situation to another. In each case, we need to identify the mischief we're trying to address and come up with regulation that addresses it in a narrow, targetted way that does the minimum of damage to the norm of freedom.
In the case of Wilders, I don't know all the accusations against him in precise detail - it's difficult to get a handle on this while relying on English-language sources. But as far as I can tell, all or most of what he is accused of should fall within (what I consider) the proper protections of freedom of speech. At least some of it is proper matter for publc debate. If he's found guilty of anything, I hope it turns out to be something that most reasonable people really would consider beyond the bounds of tolerance. At the moment, I don't see anything like that.