looks like rendering adblockers extensions obsolete with manifest-v3 was not enough so now they try to implement DRM into the browser giving the ability to any website to refuse traffic to you if you don’t run a complaint browser ( cough…firefox )
here is an article in hacker news since i’m sure they can explain this to you better than i.
and also some github docs
Because that version of ublock is already less effective. The long play is ending ad blockers and this is another step to achieve those ends. If you can’t see that then I’m sorry but it can’t be much more obvious than it already is.