The difficulty is that what we tend to do in public opinion polls favours simplistic solutions. When the public believes that sentences would make them safe because many political leaders, many police officers, and so on tell them that harsh sentences will make them safe, one can hardly blame the public for believing this is the best route to safety. The fact that research shows that it's not the best route to safety, of course, goes unsaid.
In addition, to follow up on some of the remarks that were included in your question, the difficulty is that when the public is asked these questions, there's seldom a follow-up question. Let me give you an example. Mandatory minimum penalties, which seem to be very popular with the current government, are also seen as being very popular with the public. I'm sure the government has done more recent public opinion polls than I'm aware of, but when sensitive polls have been done, there's often a follow-up question on mandatory minimums.
The first question will be to a representative group of Canadians, asking whether they favour having mandatory minimum penalties for certain serious crimes. As the government will tell you, Canadians say they favour mandatory minimum penalties. If you stop there, you'd have less than half the story.
The problem is that if you do a follow-up question, which asks if they think judges with reasons should be able to give sentences less than the mandatory minimum penalties if the circumstances of the offence warrant it, a majority of Canadians want that too, which is in effect saying they don't want mandatory minimum penalties. I think they want these things because they're told about them. They believe that sentences are much more lenient than they are.
The studies I've done over the years--and similar studies have also been done in many other countries--would suggest that what the members of the public are responding to is their belief about sentences, not about sentences themselves, because, as we all know, very few sentencing hearings--or trials, for that matter--are covered in detail in the press. One hears of a serious assault or a sexual assault or something of that kind for which the person only gets a particular sentence, and of course what one doesn't know is what that person's role was. One doesn't really know the facts of the case.
What we do know, from my own research and from other research, is that when people are given detailed information and know the facts, they're much more content with the sentences handed down by judges than they are if all they have is a description. Then an ordinary case can be made to seem sensational if the sentence looks too lenient.