The only thing surprising about this is that these printers hadn't already printed enough random garbage to get disconnected/firewalled off from the internet.
The number of printers from a simple search [1] that have no authentication is staggering.
That was astounding already 20 years ago. Fax spam was out of control then to such a degree that Congress roused itself to pass legislation with teeth, yet it occurred to no one to send printer spam. The only thing that would connect to our printers was viruses, the probable target was port 631 with buggy CUPS or other LPD daemon behind, because every few hours the printer would run off a page with just a few gibberish letters.
The number of printers from a simple search [1] that have no authentication is staggering.
[1] https://www.shodan.io/search?query=printer