OK I see where you stand. Like you, I do not like to see some product being touted as "open" just because you can see some lines of code that are made unusable by not providing some important missing pieces, or obscured, or for whatever other mechanism.
Words have indeed a meaning, but that meaning is not purely decided by some organisation, steering cometee or authority, but by what idea they evoque to those who use them. Refer to the old debate about "free software" vs "open source" [0]: almost the same technical definition, but quite different meaning.
Most "fake" open source products are produced by companies who are fundamentaly unwilling to cooperate because they want to keep the possibility to milk customers once they have succesfully attracted investors.
I might be wrong, but I have the feeling that this is a very different scenario, if only because the potential for becoming filthy rich by selling printer parts seems slim. I believe they genuinely want to empower users, without working for free for some industrial company that could just exploit the design without contributing anything back. Empowering the user meets the definition of open source for me.
I wish we would not be so harsh against good-spirited creators because they miss to check all the boxes of the official definition of open source (tm). Maybe I'm too idealistic, wouldn't be the first time.
https://www.gnu.org/philosophy/open-source-misses-the-point....