Either this is complete bullshit or HP is over-engineering

It's not bullshit. Wether or not it's "over-engineered" is debatable... a lot of seemingly simple technology is crazy complicated these days.

For example some USB-C cables are a simple cable with four pins soldered to four wires and a bit of plastic so they don't touch. Others have over 20 wires, most of them individually shielded (which means a lot more wire and a lot more plastic separating them) with incredibly complex circuit boards to detect and counteract electromagnetic interference to eliminate cross talk between those 20 wires (because even with shielding, some of the signal on one wire still leaks out onto the ones next to them).

Is USB-C over engineered? That depends if you're using it to charge your phone or to connect your laptop to an external screen/wired internet connection/power/etc. In the latter case, not over engineered at all.

The circuitry on printer cartridges don't just do DRM, they're also part of the calibration process to output accurate colours. Total overkill to print a hard copy of a payment receipt for your printer warranty... but printing a photo? I can get behind the over-engineering for that.