Morally, it seems to me that if I buy a product, I should have unencumbered use of it.
I understand how you feel, but unfortunately it's more complicated than that. First, you are not completely and entirely buying the product. Neither Epson nor Canon will completely sell it to you. They will sell you the plastic and metal but only license you the computer code that makes it work. And the terms of that license have certain limits. If you don't agree to those terms, then they don't agree to license you the firmware and/or software.
Second--and however--this whole licensing model has legal issues and problems that may require legislative solutions. In the traditional model, you have agreed on and made the contract before you pay your money. In the case of the printers, did you truly and meaningfully agree to the license contract that came with the printer firmware and software? I have no problem saying that if you download Microsoft Word and it makes you read the license and agree to it before it installs, then Microsoft it totally within its rights to expect / make you abide by the license--at least as long as you can easily enough get your money back if you refuse to agree. On the other hand, if you've not only spent your money but spent a substantial part of it having a 100-pound (45 kg) printer delivered to your home or business--without having first agreed to the license--then it's not as simple as declining the license agreement, having the installation stop, and filling out a form online for a refund.
Third, at least in some parts of the world, laws like the Digital Millennium Copyright Act (U.S.) impose additional restrictions on what you can do with what you see as yours. You might think those restrictions can be abusive in some circumstances. And I might agree with you. But the law is the law.
Back to morally right and wrong: the distinction between malum in se (inherently / morally wrong, like murder, rape, and robbery) and malum prohibitum (wrong just because a law makes it so, like running a red light) is old and important. On the other hand, it can be argued that there is a moral duty to follow laws, at least except those that
force to do something immoral (which DMCA etc. do not do).
To be clear, I'm not saying I have a good answer!