It’s hard to keep up with who-owns-who, as these companies buy and sell one another like kids trading baseball cards.
I googled, trying to find if U-Verse is dropping OANN too. I found, instead, some old articles (from about two years ago) saying tha AT&T is phasing out U-Verse. I didn’t follow that line to research to see what’s happened with that since.
Separately, I found this current article saying that AT&T has sold controlling interest in DirectTV to someone else, and it appears to be those new owners who are now giving OANN the heave-ho. Note the phrase “the formerly AT&T-run TV service” in the preview here: