My take: if it’s official promotional material, it’s not a spoiler in the classic sense. If trailers were to count as spoilers, we’d have:
The Official Rogue One Spoiler Thread
The Official Rogue One Non-Spoiler Thread
The Offical Rogue One Trailer Thread…the last one being for people who want to discuss the official trailer without being exposed to real spoilers and leaks, while not revealing trailer content to people who don’t want to see it.
That would be silly.
Trailers aren’t spoilers. Consider that official forum policy if it will end the debate and let people get back to discussing the movie.
If you don’t want to know anything about a movie you don’t belong in a thread about that movie.