However, with respect to the GamBoy itself, the issue is that when I buy a GameBoy, I am not able to inspect it, nor am I able to correct it if it is not not working properly. The GameBoy is not unethical in itself. It is forcing your customers to accept a "No user serviceable parts" license in terms of the software that is deemed unethical. Not being able to inspect the code to see what it is doing may have ramifications for the user -- perhaps not so obvious on a device that has no network, but it is where it starts.
One of the big problems with the Free Software movement, IMHO, is that it has been confused as being a software creation issue. It is not. It is 100% a consumer rights issue. One of the most important parts of free software is that if I did not give my software to you, then I have no responsibilities towards you at all. If I don't give you a binary, then I never have to give you source code. If you get the binary from somewhere else, I still don't have to give you source code -- the person who gave you the binary does.
This is about choosing a license that treats your customer well and about nothing else at all. For decades people have wittingly and unwittingly attempted to spin this as some frothing at the mouth religious issue. It is not. It is purely a consumer rights issue.