I was looking for one of the many YouTube videos I've seen in the past of early commercials with doctors recommending smoking Camel cigarettes. So far, nearly every one of them has confronted me with a black screen with the text,
"This video contains content from New Video Group and dig dis, one or more of whom have blocked it in your country on copyright grounds."
These "doctors recommend" commercials are sometimes 50-60 years old and were on free over-the-air television.

For reference, here's one that hasn't been blocked as of this morning.
https://www.youtube.com/watch?v=D-y_N4u0uRQ

I guess I don't clearly understand when anything that's been broadcast over the air is permissible to use in a YouTube video, as it seems to be a criteria that gets many videos blocked while I've seen countless videos with broadcast content remain unblocked.

Anybody know what the differentiators are?