Oh, this is scary. Drupal and Wordpress rely on Imagemagik. The amounts to a huge amount of the internet as a whole.
I'm completely unsurprised about these bugs given the number of serious problems I ran into. Granted, that was something like 17 years ago, but these veteran projects have a tendency to hang around on life support for decades. Projects that are huge messes don't generally get cleaned up without massive outside pressure (see: openssl).
It's an SEO thing. Searching "resize image" would almost always lead to ImageMagick examples that would work well enough to not require looking elsewhere. Almost every time I've used it, it's been for a few simple image operations (downsize, rotate, etc) that happen once on a user upload of a tiny site so performance wasn't a concern.
But both have plugins/modules that you can use to switch the library to ImageMagick very easily, and some plugins/modules would require ImageMagick for specific functionality.
I work at a hosting company, really hoping this PoC is more complex than is implied in the post. So few people actually patch/update their boxes with any degree of regularity.