I appreciate your taking of a balanced perspective, but I still don't think comments like the below are fair:
I could not actually concieve that anyone could be insensitive enough to consider a crime as vile as this a suitable subject for comedy
The crime itself is, of course, not the subject of the show. The show is about Knox's experience as the victim of a miscarriage of justice and media persecution (both driven by misogyny).
The two are connected, but I think it’s unfair to collapse the distinction between them. This isn't something akin to, for example, Shannon Matthews: The Musical (which was directly about the crime and purposefully in bad taste).
I also don't think it's entirely akin to something like The Producers (either the original Mel Brooks film or the more recent mega-successful musical), but I think it's worthwhile to consider the range of responses to The Producers (paricularly within the Jewish community and among Holocaust survivors).
To some, comedy about Nazism was inherently unacceptable, made light of an atrocity, and was deeply painful. To many others, it was something of a triumph over Nazism - cathartic, and helpful in processing trauma.
Using comedy to process the terrible is nothing new; it’s a long-standing, deeply human response (as is taking offense).
I don't think Cartwheel really compares to standard edgy comedy because, in a vacuum, the topic of the show is the way Knox was personally victimized.
Undeniably, it also unavoidably invokes the actual killing of Meredith, which will naturally cause genuine upset to many - though by all accounts, the murder itself is barely addressed in the show, which aims (and for most, seems to succeed) to handle it respectfully.
And I do think it is worth pointing out, again, that the show isn't a comedy in the truest sense - rather it has comedic elements (targeting misogyny, Knox herself, and certain perceptions of her) and appears to have powerfully resonated with many women, including survivors of violent, misogynistic crimes.
As something of a tangent, much of the tabloid reaction to this is really irksome, given the grotesque way in which they cashed in on Meredith's death and their direct complicity in what happened to Knox. People are entitled to feel however they may about the show, but seeing certain sections of the mainstream British press allege moral bankruptcy -apparently without any shame whatsoever - rather leads me to consider the show important.