The site appears to been hugged to death by HN. The rate of such incidents makes me wonder whether there are good reasons for so many websites not to use CloudFlare or if it's the result of plain old incompetence of the respective webmasters.
Not using something that cannot help in such situations is a good reason or even merely sanity. The problem is websites want to feed you some cookies and generate pages dynamically for each visitor, so things like full page caching don't just work, they require special considerations. At which point setting up such set-cookie stripping caching on the webserver would solve the problem anyway.