Op, I'm not victim blaming here. On the contrary, I've said from the start that I agree with what you're saying, just disagree with how you're saying it.
For the record, I don't go around feeding animals that don't belong to me, so we're on the same page there. I also understand completely that for some people animals are like their children. For most, there is a distinction though, and as a group humans are speciesist. When I spoke about injury to children and animals being considered differently, I meant legally. Comparing feeding animals to feeding children, as you have repeatedly done, isn't an analogy that works for lots of people.
You have set up this thread as a rant against people who don't know the dangers of feeding horses that don't belong to them. You claim they are foolish and ignorant and entitled, as the dangers have been so widely disseminated on news and social media outlets. But, I think you are mistaken..I really don't think they have, unless you have a particular interest and such matters are on your radar. On the other hand, I grew up reading books where feeding apples and carrots to horses was mentioned as an enjoyable child-friendly activity. So, I do think there is some justifiable confusion there for many, particularly those unused to horses or other animals.
I agree with you that people shouldn't go around feeding other people's pets and animals. However, I do think that proper signs and fences should keep most well-intentioned and law-abiding people away from horses. Unfortunately, there is always a smaller group of people who will take the law into their own hands, and you will need extra security if you want to prevent them gaining access to your horse. There is no other option. It's up to you to assess the extent of the threat and protect your horse accordingly.
You do seem to be lumping everybody into one large, ignorant, entitled category which I find objectionable. The majority of people will respect informative signs and fences and will certainly not want to risk hurting an animal. We don't appreciate being told how stupid we are and I should think you will find this approach counterproductive.