Drupal is a heavy application for sure, but it's also used in a lot of very high-volume places (sometimes in ways that you might not expect - for instance, va.gov is (sorta) built with Drupal. As of a few years ago, all of the NBCUniversal sites were as well). It takes some TLC to get it running properly. The ancient version that this site is running (Drupal 4.6 it looks like - released in 2007) probably just can't handle it.

(full disclosure, I occasionally contribute to Drupal + work/worked on the sites mentioned above)