The Italian Supreme Court says, reasonable doubt means reasonable alternative scenario. "Resasonable" means, it must not be a sequence of things merely possible in rerum natura, but remote and improbable. A reasonable scenario cannot be made with a sequence of weaker or improbable explanations.
Machiavelli,
I think most of us believe it is "remote and improbable" that 1) Amanda and Raffaele randomly and inexplicably decided to team up with Rudy to kill Meredith for no real, known, concrete reason, 2) That if they DID decide to randomly take part in a sex game ritual with a stranger (or whatever), they could do so without leaving any evidence of themselves in the murder room (contaminated and unreliable bra clasp noted), and 3) Meredith's gastric emptying time defined by t lag exceeded the median by about 5 standard deviations and exceeded the 97.5% confidence interval by 40 minutes. (The further you get from the median the more improbable the scenario becomes.)
Now, put all these
together, and you have a ridiculous and ludicrously impossible hypothesis.
Contrast this with Rudy the burglar acting alone. Climbed through a window (shown to be possible). Killed Meredith when she got home (obviously possible). And fled the scene (obviously possible). This allows one to get much closer to the median with respect to gastric emptying time as defined by t lag (more probable by definition and the axioms of probability theory). One does not have to postulate a crazy set of circumstances as to why Amanda and Raf left no evidence in the sex game murder room (contaminated bra clasp noted again). And we don't have to postulate some bizarre scenario as to why they decided to team up with a stranger to murder a roommate for no reason. This all seems plausible, probable, and likely. Far, far more likely than the group murder impossibility.
The only piece of evidence left is the knife, and multiple independent experts, some of whom are the absolute top forensic geneticists in the field, have explained how the result is due to contamination since robust LCN procedures weren't followed. Now you have nothing else to explain. No other implausibilities. The lone burglar and murderer scenario is simple, easily explainable, and far more likely.
We are being honest when we say no one here understands why you think the sex game ritual scenario is probable, likely, and makes sense, but the lone wolf scenario is implausible and unlikely. We really don't, as it contradicts everything we have ever known and learned about science and rationality. You simply saying it's not likely and science is wrong doesn't make it so.