I say this as someone who has not purchased one, but is considering it.
I used to be a reMarkable owner (until I lost it :( ) and I agree that the devices are very user-friendly in terms of hackability and ability to use it long after the company itself is gone. Getting SSH access by flicking a toggle in the settings sounds like the opposite of "hostile to the community".
Searching for this I could find only a single example from 4 years ago where they sent a C&D to remarkable-explorer.com. Aside from the copyright issues, this site seemed to be using non-public APIs and asking the user to enter authorization tokens directly on it. I don't have all the facts but I'm not surprised this would be problematic.
I heard boox was very not gpl comiant too