That's an interesting point. I'll be straight, it's lifted right from https://istlsfastyet.com. And cio.gov is in the HSTS preload list [1] so (once the list makes it into stable channels) the chances of the domain being downgraded to plaintext are pretty low. But I had not thought of that angle. Hmm.
[1] https://18f.gsa.gov/2015/02/09/the-first-gov-domains-hardcod...