It's extraordinarily difficult to 'give details' in a completely neutral frame. Without knowing the details of the study, its hard to say more. It seems likely to me that they probably found what they were looking for.
The point that the study was making is that the vociferous folks frothing from the tabloids aren't operating from an informed position, so their opinion shouldn't be held as the canonical one to base policy on.
My favourite example is this: Politicians love to say "it's the will of the people" on topics like this. "Hey, you industry professionals might not like it, but it's what the uninformed general public want". Strangely, they never seem to take the same attitude when it comes to their own pay packets - all of a sudden it becomes "what the public doesn't understand"...
People who advocate eye-for-an-eye (or in this case more-than-an-eye-for-an-eye) should be kept well away from the judicial process. The legal process should be about improving and protecting society, not simple visceral revenge.
The law institute in my state did a study where they found that when they polled the public and gave them details of the cases, the public actually suggested shorter sentences than were assigned. A far cry from the short-sighted 'hang-em-high' knee-jerking you see in tabloids.
Anyway, do we want a society that when you stumble, helps you back on track, or one that says 'fuck you' and kicks you in the face? People actually advocated those visceral punishments need to be called out on it, because they don't contribute anything useful and need to understand what it is they're actually saying.