I have written previously how easy it's to steal people's ad revenue in YouTube, pretty much with complete impunity, and how YouTube helps big corporations steal people's intellectual property.
Here's another way in which the YouTube copyright system is broken:
Suppose you make a 15-minute video full of original content created by you, but also where, here and there, you use short clips from movies, TV series, music videos, or other type of content. These might be something like 2-3 second clips, and there might be 20 of them, from different completely unrelated shows.
One of the corporations owning one of those original works may well copyright-strike your entire video, and take all of its ad revenue for itself. Yes, even though the video also contains material owned by other corporations, which may not be in any way affiliated with this one.
So yes, because your 15-minute video, with 14-or-so minutes of completely original content, contains a 3-second clip of that corporation's work, plus clips owned by other unrelated corporations, this one corporation gets to claim ownership of the whole thing. Your content, and all those other clips.
I have no idea what happens if another corporation later makes the same claim, but it seems to me that the first one to get there gets to keep the profit. Which is really twisted considering that this one corporation is effectively benefiting from the work of several other corporations, without permission.
You, as an individual person, have only two possible choices: Dispute the claim (which depending on the corporation might go as far as to the courts), or just remove the video (at least corporations can't stop you from doing that, as far as I know) and upload a re-edited video where you have removed those 3 seconds of infringing content. (Viewers are seldom happy with re-uploads, especially if you are a popular YouTuber. But usually you have no other options.)