Insulin is a vitally important hormone in your body. I know because as a type 1 diabetic, I frequently know what it's like to have too much or not enough. It is the hormone that pushes fuel into the cells and makes you grow. Do you consider insulin evil? Instead of talking about insulin spikes, should we be talking about glucose spikes?
It's seems a bit silly to personify any hormone as "good" or "evil" (although testosterone has made me do some pretty bad things over the years).
The problem is that your metabolism never evolved to deal with the kind of blood glucose spikes that a diet comprising of mainly neolithic refined carbohydrates promotes. Too much blood glucose leads to too much insulin, and too much energy being pushed into your cells, eventually causing insulin resistance and T2 diabetes in people like me. As you say, the problem is refined carbohydrates, not insulin.
For T1 guys like you, with a badly crocked pancreas, you'd be dead without injected insulin, so I can understand that your relationship with it is different than mine.
Since its already been pointed out that insulin isn't "evil" since no endogenous hormone could be good or evil really, the point is excessive insulin is associated with aging, suppressing antimicrobial peptides, and hardening of the arteries, and insulin resistance in the brain is associated with alzheimers to name a few things.
Too much insulin, and you become insulin insensitive. Insulin also causes hunger. I agree, the effects of carbs themselves are also involved in harmful effects, like glycation, body fat and lipid alterations.
I dont think any natural body compound is evil. Or any macro/micro. Its just that your body has upper limits of tolerance.
Insulin is more of an inhibitor than a storage hormone. During the 60s and 70s was the 'black age of endocrinology' where this idea that insulin is a fat storage hormone came about. Its wrong though. Diabetics don't need insulin to store glucose, they need insulin to prevent the liver from flooding their blood with glucose after they just eat a bunch of glucose.
Fructose Glucose and Sweettooth 2 Answers