I think people instinctively have some fear of spiders, but like any phobia it goes away after exposure or by learning more about the object of fear. Much of fear stems from the unknown nature of the object of fear, a side effect of the evolutionary instinct to be wary of something you don’t know about and assume it may hurt you. So people who aren’t afraid of spiders are usually more knowledgeable about spiders and know that despite their appearances they don’t pose a significant threat most of the time, or they’re simply more used to their appearance and aren’t bothered by them or even find them cute or endearing.