Yes, it is our fault for believing Netlify had contingency plans as hosting is their core business. We're fixing this mistake now so that our customers don't have the same experience.
Communicating about risks OR outages are both hard, and every company has both. I'm actually a happy (though impacted) Netlify customer. But it's completely bizarre to me to try to invalidate this customer's complaint.
[1] https://web.archive.org/web/20200303050851/https://docs.netl... (search "flattening")