I work at a design agency. Most of my coworkers have seen this site before, and generally agree with it. But we still propose designs with carousels to clients.

A lot of our clients are obsessed with what content is "above the fold". Never mind that "that fold" doesn't really exist on the web given different screen sizes, and never mind that users are more likely to scroll down than click slides. Every executive simply must have their all-important tidbit at the top of the page.

A carousel is a way to solve this perceived problem. As long as no one actually needs to see the content anyway, they at least aren't actively detrimental to the overall user experience.