Thank you, SMK. dgfred put in a lot of work comparing not just apples to oranges, but to pears, peaches and mangos.
But as you note, with the exception of Manson, none of the cases fred cites have an actual perp such as RG, whose presence and participation are undeniable.
As for the Tate/LoBianco murders and despite Mignini's wild theories, Amanda Knox is no Charles Manson. Prosecutor Bugliosi spent months in court demonstrating the hold Manson had over his followers; there is no equivalent evidence for Knox, except that she allegedly moved her hips suggestively.