Well, adblockers don't copy the copyrighted content. They just control how it's rendered on the user's machine. Copyright cares about making copies and especially distributing them.
You have a point on this, I recognize, but it still seems a very thin line to walk (for X) - at least morally, because I don't think they are actually loosing real big money to anyone.
X doesnt own msot of those copyrights, except where its elon musk's own posts.
i dont think the actual copyright owners care, given they put their content onto a vaguely public view where they aim to get the most traffic to something else they are doing
Xcancel isn't copying the copyrighted content either. It takes the raw JSON/HTML data from twitter/x via reverse proxy and redisplays it on xcancel, as opposed to twitter/x. How is that copying?