

Depends how it is done
Full console brick? You have an argument that will surely end well against the legal team that puts people into indentured servitude.
Disable of all online functionality? Perfectly valid and no different than banning someone from a store.
And the latter effectively provides the former if you can’t download any updates, connect to any online servers, or even download your game from a “game key card” or whatever the hell they are calling those.
Ethics are very much a personal thing.
That said: it is conceptually no different than any business banning someone. If you were to, for example, masturbate in a Rain Forest Cafe, they would be well within their rights to never allow you back on their properties ever again.
It is obvious Nintendo finally figured out what Ubi et al did… 15 or so years ago and is making EVERYTHING online. That way they effectively brick a console by turning off updates and immediately locking it upon authenticating with the chat server or whatever.