Seems Youtube is hitting a lot of people.. lately so they don't have to pay them..
This is google's official list but they clearly have many others not advertised.
https://support.google.com/youtube/answer/6162278?hl=en
Here are a few content "quality" examples that can get you demonetized. Found this posted by a guy on youtube who had been demonetized and this was the reasons youtube gave.
Third-party videos stitched together with minimal-to-no changes
Third-party content compiled without a narrative
Content uploaded somewhere else first
Content uploaded many times by multiple users
Note: Copyright claims and reused content are different. If you upload a video that contains copyright-protected material, you could end up with a Content ID claim. These claims are issued by companies that own music, films, TV shows, video games or other copyright-protected material. Reused content means significant use of any pre-existing content that you did not create yourself.
If you want to create content that can be monetized, here are some best practices:
Add commentary or show your presence in your videos (voice or on screen)
Link back to your YouTube channel from your website
Provide more context about your work in your video and channel descriptions
The channel in question is posting police chase/body cam footage. Stuff that tends to be public domain so it's not copywrited in most cases. The problem is he doesn't do any sort of narration or add any sort of dialogue.
If he simply added some narration to the videos he probably wouldn't have been demonetized