>It is unreasonable and impractical to expect individuals to abide by it in their day to day life.
It is unreasonable and impractical to expect everyone to abide by it. It is not at all unreasonable and impractical for a particular individual (e.g. me) to abide by it.
It is unreasonable and impractical to expect that if I leave my house doors open when I'm at work that no one will ever steal anything from my house. It is not unreasonable and impractical for me to abide by the moral principle of not stealing when I see a house open day after day.
So I agree with you - I don't expect all of society to abide by the principle. Yet it doesn't somehow exonerate their behavior when they violate the principle.
>Many people do not have a clear understanding of what it takes to prove guilt in court (and also do not understand what can derail a conviction) and would be surprised to learn how difficult it can be in some situations where there is (to the layman) clear evidence.
In a comment further down you point out:
>Outside of the legal system “innocent until proven guilty” is a very common cause of the revictimisation of victims.
I think that's a cop out in response to a cop out. Yes, certainly some people (in my experience, a tiny number of people) will invoke "innocent until proven guilty" to avoid any kind of burden of responsibility to the victim. In the vast majority of times I've seen it invoked, it is someone pointing out that others are jumping to conclusions, and the evidence is slight, and often that one person's claims have much heavier weight than others. A not insignificant number of these (in my opinion) involve fighting back at a bias of sort (race, gender, class, etc) where one person is being given more weight to others.
When it comes to issues where the parties involved know one another (i.e. not someone commenting about a case on the Internet), people invoke it far, far more often to counter mob mentality and perceived biases than they do to avoid making a decision.
The legal meaning is irrelevant to most people who invoke it. I rarely see people (in real life, outside of message boards) saying "Well it hasn't been proven in court, so innocent until proven guilty". They apply it to situations in front of them, involving people they know. And they are saying "Really, I don't see strong evidence for it."
Now yes, at times the victims are revictimized. No one has solved that problem. In my life I've seen it way too many times that something bad happens to someone, they need someone to blame, to the point of constructing a narrative in their head that they believe, which is why people say "I don't doubt he/she believes his/her story, but I need to determine if it is true."
(Not talking about serious issues like rape, but I see this behavior from victims very often when, say, theft is involved).