Kind of a weird world we live in where intellectual property gives someone else legal power over what we may do with our own devices, but conversely our ability to do things with our devices that is within our legal right is not considered our property.
That's not what's happening here. HP doesn't have power over what you can do to your printer. If you want to modify your printer so that it allows for ungenuine ink to be used you are free to do so.
HP modified other peoples' printers without genuine[0] consent to make the printers less valuable. It should probably be illegal for them to do that.
I imagine there isn't an existing criminal law covering that and I'm not in favor of interpreting criminal laws creatively to expand their scope, however I could be convinced to support making a new criminal law to cover this kind of behavior.
[0] No doubt, they have some fine print in a clickwrap agreement giving themselves permission.
