Whether he was claiming that this was some sort of "ritual sacrifice", or not, is "not important" to the straw men makers, maybe; because what they they like to do is to overlap and obfuscate.
Mignini considered "not unrealistic" the possibility that there was some ritualistic element in an act that was defined "festino"; or in choosing the day for it; "festino", a meeting that must have had some sexual content and some element related to violence, that might be acted or just represented at the level of a game (a sexual humiliation game, maybe).
This was an idea considered by Mignini.
But Bill Williams - and some of his comrades - forget to say that this is NOT a "ritual killing scenario". The "act", that was portrayed as maybe having "not unrealistically" an element of ritualism, wass not a killing. Maybe not even a crime, and maybe they didn't even plan in advance to target Meredith with any action. The object related to the ritualistic elements, as we can read, was a festino. An ironical Italian word that means: a little game, a little play. And the ritualistic element may even be meant only as inspiration for the day of its occurrence.
Now, let's put something in clear, not to confuse my opinion with that of Mignini. I think the speculation about this possible "cultural" element was inappropriate, I don't believe this element could realistically belong to the intention or psychology of the perpetrators, given the cultural level of the suspects.
I do not agree with some of Mignini's ideas, like those about sociology; for example I dn't believe it makes sense, on sociological level, to put in relation a penchant for Marilyn Manson with possible deviant behaviours. And the attempts by Mignini and Maresca to make sense of what cultural elements or aspects might have played a role in the psychology of the suspects to their decisions, they basically express their own culture, rather than having a scientific content.
In my opinion theirs is a very "rationalist" worldview actually, used to sophisticated literature, somehow of the most "traditional" European kind, including libertine and enlightned sexual material, and they live in a world where things usually have some reasoned aspect or have some sophisticated culture attached. I bet De Sade or BDSM fetishism would look like normal stuff in that view, like Dolcetto d'Alba with Gorgonzola. But in fact the cultural level of the suspects did not allow to such speculations to be realistic, in my opinion; I think they wouldn't chose a particular day because inspired by Halloween as much as they would unlikely handle a Dolcetto d'Alba with Florentine chops rather than a Pinot Bianco with shrimps.
But I also understand that those topics are irrelevant to a murder trial. A prosecutor is not supposed to be a sociologist or a psychologist. Neither is a judge. Mignini is a very professional investigator, but his sociology skills are amateurish, and has no degree in cultural studies nor in psychology.
At an amateurish sociological level, it is fair to think that maybe the suspects were somehow influenced by a Halloween themed atmosphere that gave them inspiration. It is inappropriate, in my opinion, but it is irrelevant to the scenario.
What matters is what Mignini put forward, substantially, was a non premeditated murder scenario; which was, obviously, a non-ritualistic killing; it had nothing to do with satanism, and it is a fact that he never employed the word "rite".
It is not true that this was the "entire catalyst" in Mignini's scenario; this is not true insofar as, in fact, Micheli himself pointd out that the prosecution dropped this element during the very preliminary hearing. This possible ritualistic element about dates was dropped not only because it was inappropriate, but also because it could be easilly dropped, since it was irrelevant.
And also, note, that even the "catalyst" element would be, in fact, something irrelevant in the scenario. It is an intrinsic property of a catalyst, that of being irrelevant: by its nature a catalyst is only a trigger. A catalyst cannot be the motive.
Thus, the ritualistic element - which you admit it was only a catalyst - could be, in Mignini's scenario, at best only a contextual element, not the motive.
I believe that he felt may have been opportune to speculate also on this possible contextual element before the judge, just because he found himself without much to say about a motive, where he lacked information about.
He doesn't use the word "ritual". And if you read the previous paragraph of p.46, you will notice how he points out that the main reason for the choice of the day - or better the main "catalyst" - was not the ritualistic element, but the fact that Meredith and Knox would be at home together alone, for the first time, on that night.
And if you go further back up to p. 43, you will read how Mignini expresses the view that this was a random murder, that is a murder in which there are many "factors playing" a causal role; among those he mentions, at the end, some aspects of the suspects' personalities, which he sees as co-factors of risk.
Most of his observations, in my opinion, are correct.
The straw men makers would only pick up the inapproriate, irrelevant contextual speculations, and forget the rest of the arguments.
Now, in fact Mignini doesn't say they were planning to commit something upon Meredith, some kind of act against her will. He suggests something slightly different. He suggests they intended to involve her in a sexual game. Mignini does not jump to say that they were aiming at committing a ritualistic act on her or at committing a violence: he says they meant to "drag her into a game".
This dragging her into a sexual game seems in fact an actual part of the motive, it has a causative effect, it's not just some contextual scenario.
But still, this dragging Meredith into a sex game is not - in Mignini's argument - the whole motive. There is another part of the motive, which he points out, something he mentions in the same paragraph and he assume it may have had a causal effect - even if it's unclear how this plays in a narrative the other possibilities - that is: Meredith's rent cash money. This one, for Mignini, was another part of the "real motive".
Mignini doesn't build a narrative but mentions these two possible motives: desire to drag her into a sexual game, and something that has to do with using her money.
He doesn't specify further any narrative or scenario - it's clear he doesn't have information - but those are the elements that he points as the most probable elements of the motive.
Remember