Parent comment didn't imply the contrary. "stop promoting nonfree software" doesn't mean "stop only promoting nonfree software".
>even the LGPL shows that absolute avoidance is not always the best thing to do regarding closed-source code
If you ask the FSF, the LGPL should really be used as a last resort. Unity is not too common yet (and hopefully will never be as long as it remains proprietary), so I don't see why we should push it forward by helping its integration. Same goes for HTML5's EME. I'd rather have a purely open platform with less features and popularity than a platform with an open base and countless incompatible binary blobs sitting onto it. And even the abomination that EME is would at least be an actual standard.
>Unity engine is a proprietary codebase, they also have lots of code that is FOSS
If you can't build it, it's not worth integrating. The only thing this is good for is making a FOSS alternative (although I guess they keep the important bits secret). I'd be using Google Chrome if "99% open source" was good enough. By using Firefox (though Chromium would be fine if it weren't for the user-hostile features), I precisely want to keep a clean FOSS platform. Conversely, I only use an Android ROM because there's no good alternative, which is not the case for Unity. So I wish they'd keep it out for now.