I see what you mean, kevinom67, which is why I didn’t really want to take a “poll”, I was more interested in people’s memories of how common this was in their childhood. For example, whether their siblings, friends or classmates did it, and how many of them. I didn’t really want to hear “I did” or “I didn’t” responses, although of course I got quite a few. Due to the considerations which you pointed out, I know I can’t really base any kind of conclusion on these. I also knew only one person who did this when I was young, and that person did turn out to be a bit of a sociopath. But I revised my estimate to 1/3 based on what people told me about how common the practice was amongst their friends and other children that they knew.
I’ve got a new hypothesis now… that geographic location may have something to do with it. For example, I come from a place where insects invade people’s homes in droves. So killing insects is a household chore which must unfortunately be carried out to prevent the insects from totally taking over the human world. Maybe this detracts somewhat from the childhood fascination with insect dissection. Just a theory…