Just reading through this, I think you are missing the point in respect to the original question posted and what
@mecalec13 is trying to say.
The channel is question is 100% monetized and in the YouTube partnership programme. The way this can be checked is by looking at the page source and searching for the monetization enabled =True/False. This is what Mecalec13 explained. This answers the original question posed by the OP.
But, I get what you are trying to say. Possibly not all the content on the channel is monetized by the channel due to copyright content and could be going to OG creators.
BUT, I personally think the content is monetized and earned by the channel solely as they:
1. Wouldn't bother creating, editing and uploading the content if they just get copyright striked every time.
2. They would have most likely been striked with multiple claims - thus not having monetization enabled (which we know they do have enabled)
3. They have clearly added to the content with voiceover, transitional editing and music etc. This is enough to deem it fair use, hence why they are monetized and probably earning a lot of money.
Hope this clears things up.