My phrasing was somewhat hyperbolic, but I basically said: "Do you honestly think that a person, in the middle of a natural disaster, trying to determine whether or not their family and friends are okay, gives a sh about 60fps animations?"
The real value of React Native is that it allows engineers who know React (and React is really, really easy to learn btw), to build great feeling applications without putting in a ton of effort. Sure, it's possible to get close enough on web, but it's really, really hard to do so.
One of the things we tout in product infrastructure at Facebook is that when building frameworks, you need to enable engineers to fall into the "pit of success". The asynchronous nature of this implementation allows application logic to be run off the main thread by default, which we think is a huge advantage over a traditional web model.
I think the poor reviews of Facebook's HTML5 mobile app shook the company to the core and they swung a bit far in the other direction, abandoning the possibility that the web will ever be mobile ready. I think the truth lies somewhere in the middle; no, you can't get native performance from the web, but you can get close. And every year it gets a little closer because phones are getting ridiculously powerful.
All this said, I think Facebook's approach to the platform fragmentation problem is clever and worth checking out, but I'd still bet on HTML5 over the long term.
It feels like there is a bias against web based apps in general because I usually have a bad experience with them or stop using an application when I get annoyed with the user experience. I'm sure it's possible to create a good user experience with a non-native toolkit. It just seems like the people that really give a damn go native in order to offer a better experience.
I would argue that for most apps, the interface can only get in the way - Facebook included.