Look, there's no dispute that Facebook is an assault on the 'open web' because it's a walled garden where the data only flows in. In fact, on the HN thread for Gruber's previous post about Google's AMP, I defended [1] some aspects of AMP because at least it tries to be distributed vs. Facebook, and in that post I echo much of what Gruber would later say.
But sadly, today's so-called 'open web' is just as much of an assault on the open web: trackers, cookies, and cross-correlated advertisements follow the user everywhere; every new link is literally a crapshoot which may execute arbitrary code placed there by the webmaster or their delegates. It's the devil you know vs. the devil that's brand-new every time: do I want my browsing habits aggregated to help them better target ads and content for me inside some walled garden, or do I want my browsing habits across the 'open web' to be aggregated by a dozen third parties to help them better target ads for me on the outside, while I blissfully extoll the virtues of decentralization and pretend I'm better off?
Until recently, the only way to avoid this was to spin off a clean incognito session in a browser running only one window, then close it after every pageview. Who does that? Short of a very particular few, no one.
The web is a wonderful, versatile medium of referencible documents and multimedia that we've turned into an application delivery platform; and the one thing that content silos like Facebook, Instagram, Snapchat, and Apple News get right is that not everyone cares to visit unvetted content solely judged by its URL.
[1] https://news.ycombinator.com/item?id=14384607