You download a copy of a photo I took to your computer.
I have a website that lets people see the photo, it’s a popular website
Except that photo on my website doesn’t point to a copy of that photo on one of my computers, it points to the copy on yours.
Millions of people visit my website, and each time they do, they download your copy of my photo.
Uploading that photo to millions of computers across the world fucks up your internet service. You could also switch out my photo for another one, maybe even an offensive one, but my website would still point visitors to it.
In the original post, this is what a multibillion dollar corporation, a bank, did to a not-for-profit service that keeps a historical record of the internet.
I hinted at the security implications of what happened, but explaining that would make the analogy too complex.