So I'm pretty sure I figured out why Phil was removed from the Twitch partner program. Phil will probably dispute it and call me an idiot but I think I can conclusively prove it. First off, Phil reading the email he got about it out loud on his stream, sourced from his own video on his own channel:
What Phil reads here says, verbatim, "Notice of indefinite suspension and termination for Darksydephil. Pursuant the content license agreement dated...that I guess I signed in late 2016...between you and Twitch Interactive in respect to your Twitch account Darksydephil we're terminating your partnership agreement effective immediately pursuant to the terms contained within." This is Twitch giving the exact reason Phil was removed from the partner program. He violated the content license agreement.
The content license agreement is a specific part of the partnership agreement that he was required to signed after they updated it when he went back to Twitch. What that content license agreement says, verbatim and sourced from Twitch's legal page (https://www.twitch.tv/p/en/legal/affiliate-agreement/) is:
"2.2. Live Content Exclusivity. Solely for any live audio-visual work you choose to provide to us as User Content (your “Live Twitch Content”), starting from beginning of the Initial Broadcast of any such Live Twitch Content, and continuing for a period of twenty-four (24) hours following the end of the Initial Broadcast of such Live Twitch Content (the “Exclusivity Period”), such Live Twitch Content is exclusive to Twitch (even as to you). During the Exclusivity Period of any Live Twitch Content, you will not, nor permit or authorize any third party to, broadcast, stream, distribute, exhibit and otherwise make available such Live Twitch Content in any manner. Notwithstanding the foregoing, you have the right to make any Live Twitch Content available, during the Exclusivity Period, solely via the Twitch Services. After the Exclusivity Period of any Live Twitch Content, the license to such Live Twitch Content will become non-exclusive and you will have the right to broadcast, stream, distribute, exhibit and otherwise make available such Live Twitch Content in any manner and format desired by you. The “Initial Broadcast” means the initial broadcasting, streaming, distribution, or other exhibition of Live Twitch Content via the internet, whether such Live Twitch Content is broadcast on a real-time, live basis as the subject event is occurring or such Live Twitch Content has been prerecorded and is being initially broadcast for the first time via any manner or method of streaming."
What this means is that from the moment a partnered streamer's stream ends they are not allowed to post the content of that stream on any other platforms for a full 24 hours. This includes YouTube. So, given all of this information, Phil was removed from the partner program because violated the content license agreement within the affiliate agreement by way of consistently uploading his streams to YouTube immediately after the stream every day for years. It's not that it wasn't a problem for all those years, he just was able to get away with it and Twitch either finally found out or decided to stop letting him slide.