FWIW, I think there is a slow push towards a consolidated “TV” experience which may or may not have started as result of Apple launching Apple TV+. Sometime over the last several years, there have been a push towards consolidating the streaming content into one place, so users would theoretically get a unified search and viewing experience. I think the most recent version of tvOS even did away the iTunes Store in favor of having that integrated directly in the TV app.

However, I said may or may not have started as result of Apple TV+ service because that seems like a consistent trend across the board. Even in Plex, I do a search, I get a bunch of content that they’re trying to redirect me towards (Plex’s own FAST TV service, and maybe even purchase else where if memory serves).

None of these negates what you’ve said though. It has nothing to do with TV+ service, and dude could’ve just ignored the TV app and used the Plex app if that’s their streaming source. In fact, Plex cannot integrate into the TV app because Plex cannot provide searchable metadata about content on your server to Apple in a unified fashion — vaguely recall reading something about Apple requires app to give one search end-point that will return one search result to Movie X, and there’s no way for Plex to differentiate my version of Movie X on my server from your version of Movie X on your server. So even the whole TV app thing is kind of moot.