> Actually it is.
Specifically what law did he break?
If someone leaves you a voicemail with a message you don't agree with, is that a crime?
If someone sends you a fax with the same message, is that a crime? [1]
If someone sends you an email with the same message, is that a crime?
If you connect a printer to the internet and someone sends the printer a document with the same message, is that a crime?
I'm sure someone can find a way to apply the CFAA to this, but at the end of the day a printer is not a house. A printer connected to the internet is a server that turns files into paper documents. If you don't want people using your printer, don't place it on the internet with zero authentication or access controls.
[1] advertisements are illegal, not sure about arbitrary messages.