[asplundj]

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The issue is that Kodi as a GPL licensed software is according the GPL license not allowed to not ship with the CDM (Content Decryption Module) for Google Widevine and Microsoft PlayReady because it as a proprietary binary blob is not compatible to be included with a GPL software. These mentioned CDM files are what are the actual cloused source "DRM modules" that the controversy is all about as only a few of approved companies have been making them so far for widespread use.

https://support.mozilla.org/en-US/kb/enable-drm
https://www.microsoft.com/playready/features/HTML5.aspx

To get around that GPL incompatibility with proprietary CDM modules for Widevine/ReadyPlay the Kodi software would simply not ship with those proprietary CDM module files, and instead would use the suggested workaround to rely on the CDM (Content Decryption Module) for Widevine/ReadyPlay that ships with Android (OS) / Microsoft Windows or applications such as the Google Chome / Firefox web browser to have those provide them as system services.
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If you take a look at the situation right now, this is exactly the thing people are doing (well, with people I mean libdev who did the inputstream.adaptive binary addon). Take what it´s there on Android or rely on the users to link the widevine decrypter/decoder library from their browsers.

The problem with this is, if users are doing this, they are violating the Widevine License from Google, which not only forbids distributing/copying/linking, but also the usage outside of Chrome (if you´re not a licensed partner).

So, what I would really like to see (from the end users & Addon developers perspective - and please don't get this wrong, I´m trying to make this not sound like a demand ):
Kodi (or better the Foundation) becoming a licensed Widevine Partner (which is for "free", if I remember correctly). The decrypter/decoder binary doesn't need to be shipped with Kodi, you could have an "official" Addon which downloads the library on demand. And with on demand I mean, with the users consent & only if a third party plugin requests this feature.
That would bring developers in the position to have a unified way of accessing DRM contents & would enable an "A grade" user experience for the content consumer.
I guess that would also be a good way of bringing third party content providers (most probably not the big players e.g. Netflix & Amazon, but smaller & mostly local providers) to write their own Addons & support Kodi through their content.

I don't think that doing it that way would be against the GPL, but I´m not a licensing expert, so please correct me if I´m wrong.

I think this is a very good suggestion