One involves a neutral role, in which subscribed feeds are delivered to users without modification or filtering.
The other involves an active role on the part of the platform for any number of reasons: increased engagement, removal of voices that may cause perceived damage or lack of trust in the platform itself, or other, more ideological reasons.
I've noticed an intentional avoidance of distinction, lately, between active and passive behavior on a number of fronts, from sexual activity, to medical advice and intervention, to social media publishing. It's a pretty crucial component in ethical analysis that I suspect is being intentionally blurred.