While I don't hate gnomes, that's pretty much how I feel about them. But then I feel like that about some of the other D&D species as well including the goliath. In my experience, the goliath pretty much fills a similar niche to the half-orc but I haven't found a lot of people who hate them.
Yeah, goliaths just feel like "big brute guy without the baggage". Gnomes have just been around longer and people are simply more prone to make jokes about short people or species. It's part of why the Ferengi on Star Trek, which were supposed to be a significant threat, were treated more as comic relief.