When people are shopping for an appliance, price is often the largest deciding factor. HP prices their inkjet printers low to lock in that sale. But in order to still earn a profit, they try to make money from the ink, so they lock down the firmware to block 3rd party ink.

People hate how expensive ink is, so they created Instant Ink, a subscription model. If you do a decent amount of printing, especially color printing, you'll actually save money. But it's widely misunderstood. You're not subscribing to ink, you're subscribing to printed pages. And so there are people writing nasty articles about HP because they'll pay $3 for their first month of Instant Ink, HP will send them an ink cartridge, they'll cancel their subscription, then have a Surprised Pikachu face when their printer then refuses to print with the Instant Ink cartridge, because for some reason they thought they owned the ink cartridge that they paid $3 for.

And of course, someone will take a picture of their printer refusing to print with the Instant Ink cartridge that they're no longer subscribed to and post it to /r/AssholeDesign.