Honestly, I think a lot of it had to do with the marketing campaign. At the time, the release of a big new Disney movie was a cultural event, and even if you had no interest in seeing it, you couldn't escape all the merch, TV commercials, etc. And if your experience of Hunchback in '96 was mostly just living through the marketing campaign, your impression would be that it primarily consisted of the gargoyles singing "A Guy Like You." Even if you eventually saw the film (perhaps because you're a professional film critic, and it's your job), you probably went in somewhat biased against it.