Did TCM make any announcement? Films roll from one service to another pretty regularly. As of right now, the TCM site shows They Were Expendable, Flying Leathernecks, Stagecoach, and The Green Berets. That’s only four John Wayne movies and only one western, but John Wayne has not been completely purged. I assume the other films migrated elsewhere.
The Dark Valley, a western from Austria. Well worth the time to watch. Free if you have Prime, you won’t be disappointed.