If it is a community-driven decision, up to them of course - some small communities I used to follow that are not very much connected to the rest of reddit itself have no mentions about the blackout, and I suspect most of their members are not even aware of it. If it is the moderators deciding themselves, that is a different issue - it is very interesting to follow the list of open and private subreddits in reddark!
Indeed, if I were the developers I would be threading much more carefully. While it may be true that the letter is not precise enough, access to YouTube implies a relative acceptance of the terms of service of providing the service, and it is not so clear cut as Invidious claims.
It focused on two amendments posted by EPP, allowing in principle facial recognition on public spaces for law enforcement purposes.