I think his source is the JWfanpage but from what I understood the chants in the duel trailer were collected from the original soundtrack and then mixed with trailer music.
No one on there said that. They’re smart enough to know what is from Williams and what isn’t, and that trailer music is clearly too “epic” to be from Williams. I don’t think the guy in that video knows what he’s talking about, he’s just whining about something he clearly has little experience in.
EDIT: And the rest of the video doesn’t make any sense either. He praises music that is clearly tracked as being from Williams, and the condemns music that is clearly from Williams as being tracked. His definition of themes is completely arbitrary, and only exists so he can make this great score seem like the worst thing ever.
For example, he condemns the movie for putting the Star Wars theme in places where it doesn’t refer to Luke, and for putting the Imperial March in places where it doesn’t refer to Anakin, as if those themes are supposed to be for Luke and Anakin instead of Star Wars and the Empire. There’s a reason they’re not called “Luke’s Theme” or “Anakin’s March”.