The quality of the video on YouTube is very low, even for 1080p. The bitrate or resolution needs to be higher, because it looks so poor on a 50" display
That would be nice, BUT, there are limitations on how you can stream, that includes Resolution, and Twitch is even more restrictive at bit rate, resolution, and audio. YouTube is a bit better and the PCs being used are up to the task they could bump it up a little, from what I can tell, they are steaming to Twitch and Youtube or taking the stream from Twitch and putting it on Youtube, as you watch the chat roll by there are Twitch chat postings. Not sure how that is done though.