WordPress uses a lot of resources for 404 pages. It's dumb but WordPress is everywhere. One site being hammered is one thing. Thousands of sites being hammered

WordPress uses a lot of resources for 404 pages. It's dumb but WordPress is everywhere. One site being hammered is one thing. Thousands of sites being hammered at the same time is another. The issue in the article is a current and live problem. Blocking the requests saves a lot of CPU cycles.