It gets to be a muddy situation when it comes to compilations and broadcast news... for example, Jimmy Kimmel does his "This Week in Unnecessary Censorship" by using broadcast clips and remixing them to be his own thing. I'm fairly certain the term is "Fair Use". That said, YouTube monetization rules do clearly say you can't monetize compilation content of other people's work... but for that to be enforced someone would need to issue a copyright claim, and I suspect that most news agencies aren't all that concerned with that kind of thing because it doesn't really hurt them at all.