[habinero]

They have not. CDNs are specifically meant for demo/non-critical usage, to make it easy for amateurs to try out the library.

You don't do this in any non-trivial system.

[trimethylpurine]

According to FontAwesome you're wrong. Their instructions say that their CDN is the recommended way to use their kits.

So, it's nice that you don't do this. But there's nothing special about the White House app doing it. It's very common.