It's not surprising... I mean look at them. There is an evolutionary reason why insects look disgusting to us. Same reason why feces look disgusting - We're not supposed to eat that.
Insects being disgusting could also be a learned response, kids are pretty willing to pick up and touch things they haven't seen before including insects.
However they look to their parents when doing it, or about to do it and are generally quite good at picking up on even subtle facial clues. Since kids can easily be 1 or 2-shot learners about stuff like this it's very difficult to separate innate from learned.
They're spooky because they move erratically and their bodies are so different from ours that we can't intuit where they are looking or what they are about to do.
Disgust is largely a learned response, i.e. cultural. Many people find crutaceans disgusting to look at. Rodents are also extremely polarizing. Personally I find dogs mildly disgusting because they often drool, roll in dirt and residue of urine and fecal matter can cling to their coat since they don't clean themselves like cats do. On the other hand some people find cats disgusting exactly because they clean their butts with the same tongues they use to clean their coat and maybe you.
The reason most people find insects digusting isn't the insects themselves but that insects are a signal of decay. Spoiled and rotting food attracts flies and other insects, so food with insects on it is unappealing. Countries that don't have a tradition of dairy consumption often find cheese disgusting because it is practically rotten milk.
Faeces look disgusting as you learned that it was disgusting from your parents when you were young. Its unrelated to your own evolution but is instead a memetic idea passed on from one generation to the next
I don't think it can all be reduced down to memetics because there are things which I find disgusting which my parents don't find disgusting. Like oysters for example. Though I think obviously some people are more influenced by memetics than others.
