Activity Pub is much more flexible, the tradeoff being that it's more complex. ActivityPub is basically a flexible CRUD API specifically designed for social networking, with support for federation.
You could fulfill the purpose of RSS with ActivityPub. But, it doesn't supercede RSS/atom, because the simplicity is valuable for the cases those protocols handle.
Their news room has been this way for ages. They were the Bush administration's biggest supporter in the lead up to the Iraq War. They've been anti trans for years, they were all in on opposition to Bernie.
I guess you just hire one Paul Krugman for some opinion pieces and people assume you're not a right wing mouth piece