Just to verify, are you talking about the _real_ Peppa Pig videos, or the fake, weird ones?
Because as far as I can gather using Wikipedia, Entertainment One is the company behind the _real_ Peppa Pig. If you're saying that there is also reason to believe that they are behind the _fake_ Peppa Pig, that would be much larger news, which (looking at the amount of interest in the story), it isn't.
Edit: Ah, mFixman suggests a plausible explanation:
> Entertainment One owns Peppa Pig[1]. It's likely that Content ID thinks Elsagate is legitimate Peppa videos.
> [1] https://en.wikipedia.org/wiki/Entertainment_One
That makes more sense :)