Well, I don't want to argue so it seems like we're gonna have to agree to disagree. But I do feel like you are misunderstanding how trademark works.

Trademark only protects against customer confusion, not other projects becoming popular. Reasonable people looking for the band who instead find links to the movie are not likely to think the movie and the band are the same project or brand.

Look at the examples from the patent office .

When a consumer knows what goods or services you offer, what other goods or services might they reasonably expect you to offer?× For example, if you sell hot dog buns, a consumer may expect you to sell hamburger buns and loaves of bread.

It's irrelevant that the movie is now showing higher on search results. The relevance of trademark will apply to other touring bands selling music under the name Demon Hunter, or names like "D. Hunter" / "Demons Hunted" or if the movie characters were styled after the IRL band, they might have a case. But an all male metal using Christian imagery and prayer band is quite different than a fictional all female pop band that does dance fighting. The content of the 90+ minute film is sustainably different than the content of 3-4 minute religious metal song.

However I've said my piece and I don't wish to belabour the point further. Time will tell who wins, but according to actual mechanics of trademark law the court will only rule for the band if they can show reasonable people confuse the musicians for a movie, which I think would be an unrealistic accomplishment.