It's funny how irrational it usually is. You obviously understand why you shouldn't be afraid of them but your gut doesn't care. (Something something reactionary thought and gut impulses)

I have done research with lots of reptiles and at this point I just find these big dudes cute, like uguu~ squish their faces cute. But I grew up in a house full of potentially dangerous spiders and I still jump when I see one, even though I know not to be afraid. My guess is that as a kid I probably saw my parents who are not biology-brains freaking out when I was near spiders, and I just absorbed the message that I should be terrified.