Like I said, the bottom line is it's down to the parents' personal perception of their own level of risk at any one point in time (and the level and type of risk they consider acceptable, vs the benefits of whatever activity).
There are some things that are essentially always no-nos, such as bed-sharing when under the influence of drugs/some meds/ sofa-sharing etc, and then there are risks which are harder to quantify, in which individuals may differ considerably, such as feeding method, smoking in pregnancy, infant birth weight etc.
As far as feeding method goes, you are of course correct in a sense, however I suspect that you might be reading what you want to read - Sleep Lab (and other) studies have shown with some consistency that feeding method affects the way mums and babies sleep, and that the ways in which they differ might reasonably be thought to be factors which affect the overall riskiness of bed-sharing in terms of both SIDS and accidental death.
Ultimately, there is always a combination of variables to consider, and these are often not static - they change from day to day. Parents need to be given the relevent information relating to risk factors so they can decide for themselves (and take responsibility for making that descision rather than farming it out to family/friends/health-care professionals). It is as wrong to simply say 'it is safe to bed-share if bf', as it is to say 'it is unsafe to bed-share when ff'... These are simplistic messages, as beloved of FSID and some HCPs, but they tend not to do much good in the real, multifactorial, world. I we need to see a complete shift from such simplistic simple messages to provision of information and a recognition of the importance of multiple factors and active decision making.