I’m not a lawyer, but my understanding of GPL is that the requirements are only triggered if you distribute your software

Twitch’s back-end code (server code) is never distributed to customers/users, so it ought to be completely fine to use GPL code in any way they want

Twitch’s front-end code (desktop apps, web apps, mobile apps, etc) would count as distribution, so any use of GPL code here would have to comply with the license

If an open-source developer wants to protect their code from the back-end code loophole (increasingly important as software-as-a-service becomes the dominant software use case) then the Aferro GPL (a.k.a AGPL) is probably what you’re after, as those requirements count network connectivity as distribution

they are going to apologize, release what they violated so far and once security is tighter, continue to do it