I'm skeptical that a deceptive euphemism somehow makes this less of a deceptive trade practice.

At the end of the day I'm not sure that a lock that prevents you from using non-authorized equipment/refills/whatever is very different from established practice. If they bricked the printer altogether sure, that'd be a new frontier, and it seems like many commenters have erroneously understood that to be the story, but that's not what's going on.

Are non-HP cartridges a vector for hacking? If not then what does that have to do with security?

Honestly I wouldn’t be shocked but I don’t think cheap inkjet printers are a high enough value target that you’d see that in the wild a lot.