Can you e.g. Stream a public TV stream like Sport 1 or Tagesschau live on Twitch like in "reaction" videos?
Watch YouTube videos in the stream with Facecam etc. Is it also allowed per se and is a public stream then allowed, since everyone can theoretically watch them?
No, you can't. You also may not show other people's YouTube videos. Just because many do that does not mean that it is approved…
Reaction videos are also allowed on YouTube. In the end, is it the same or not? Even large streamers show video links sent by viewers. Only music has copyright, which is then muted from the VODs. Please send the article to ToS as proof, otherwise unbelievable, thank you.
You are welcome:
Sharing other Twitch creators' content
Playing pirated games or on unauthorized private servers
Sharing content from other sites
Showing movies, television shows, or sports matches
Playing music you do not own or do not have the rights to share
https://www.twitch.tv/...uidelines/
"Sharing content from other sites" is actually enough statement…