In most settings, humans treat goblins as little more than vermin. Goblins are weak, annoying creatures, dangerous in the way a rat might be. Ultimately of little concern. They live short, frantic lives, causing trouble and breeding prodigiously. They find empty or weakened niches in geography or ecosystem to populate, and when those are filled, overrun outwards, rapidly depleting the resources (food, fuel, patience, goodwill) of the places they spread. They are nearly universally despised by the longer-lived, more-civilized races, and seem just as universally ineradicable.
So why don’t elves consider humans in the same way that humans consider goblins? In most traditional fantasy settings (read: those derived extensively from Tolkien), elves are nigh-immortal elder beings, cultured and thoughtful. To an elf whose goals and experiences likely span centuries, humans must seem obnoxious upstarts, never to mature and incorrigible in their violence, dizzyingly busy and almost infinitely resilient. How could an elf ever see a human as a peer? How could an elf see human social structures as anything beyond a child’s attempt at playing civilized?
If goblins appear to humans as the embodiment of id-driven wasteful children, humans almost certainly appear to elves as forever-teenagers, discomfitingly mature in body but never able to gain the wisdom that comes with experience. At least goblins are manageably small; all else equal, they’re still only three feet tall. A human has the ability to do much greater harm, lumbering man-children given the tools of destruction but never the temperance to match. Can a human aspire to wisdom any more than a dog can aspire to song? If a goblin dies of his foolhardiness after fifteen years of life, or a human after seventy, how much difference does that make from a perspective of seven centuries? Or six millennia?