It's interesting that they're using the Twitch name rather than Amazon to announce this. The Twitch ASN (which, incidentally, is present at 3 Seoul IXPs) was renamed to "Amazon IVS" post-acquisition. https://www.peeringdb.com/asn/46489
The streamers and viewers that will be affected by this are Twitch users, not Amazon users, so of course it makes sense that this is Twitch announcing it to their userbase and not Amazon.