With Facebook, Twitter, Instagram where content is ephemeral and infinite, I would say their design goal on the main page is addiction during that moment. More time spent scrolling means more opportunities for Sponsored posts and Adverts to display. Scrolling the homepage seems like a use case where the use is not taking intentional action, so infinite content is fitting.

If a user closes out for a moment and returns, they expect new content to populate the screen from that moment.

Is the user actually engaging in the content? That’s another story…

With examples of content that are less transient, such as shopping, news, blogs, information, or even sub-pages on Facebook, I would think the Etsy case study applies for use as the user has made an intentional navigation decision.