Despite the proprietary javascript et al, it's still arguably quite "FOSDEM-y" to spread its information far and wide to every corner of the internet making space available for it.

And in the case of youtube they make significant effort to maximize accessibility when it comes to devices being able to successfully play the videos and get the message, as it aligns with their need to show ads to as many people as possible.

I'd argue shoving informational content on youtube is making less a deal with the devil than say hosting your FOSS projects on github...

I could also just rsync the raw unsplit files on a public server somewhere, would save me time actually =)

(If you have usable FOSS Youtube alternatives, don't mind trying to use them)

PeerTube is the only obvious alternative I know of, I'm sure others here know even better alternatives.

How would you meet FOSDEM’s requirements without YouTube? And what is your proposed solution for distribution and audience reach?

In fact the FOSDEM doesn't use Youtube and still deliver live streaming only with HTML.

Peertube is well suited for events like FOSDEM. The CCC use https://c3voc.de/wiki/voctomix but a littler harder to use.

I think you are getting a few things mixed up: voctomix has nothing to do with stream/video hosting, and is a different part of the stack.

Yes, the website (media.ccc.de) is https://github.com/voc/voctoweb/, but live streaming is actually a differennt project: https://github.com/voc/streaming-website

They do interact a bit, to make it seem more seamless.