You know what? I don't really know...and after doing some quick reflection, I think that knee-jerk assumption was based off of something I remember reading from the Simpsons Archive...which is probably the very first website I ever remember reading on a regular basis. From their About Page:

http://www.snpp.com/about.html

> The Simpsons Archive cannot accept sound or movie file submissions under any conditions. Our server traffic averages 24 gigabytes per month, and housing a large binary archive would boost bandwidth fees beyond affordable limits. Additionally, Twentieth Century Fox ruthlessly defends its copyrighted work by issuing Cease & Desist orders to fan sites housing said content. While we sympathize with those who have fallen victim to Fox, we prefer to avoid legal entanglements by steering clear of multimedia.

Otherwise, The Simpsons Archive gladly accepts all submissions in the form of fan-authored FAQs, lists, guides, news and other miscellaneous items. All authors retain full credit for their works and may update them within The Simpsons Archive as needed. We ask, however, that prospective maintainers be versed in basic HTML. For further details, please e-mail webmaster@snpp.com for our submission policies.

So Fox's aggressive C&D is maybe just for audio/video? The SNPP does have a very small sprinkling of Simpsons-artwork. And maybe Fox was more aggressive with C&D back in the day, like, 15-20 years ago, when SNPP was first starting out.