Apparently they also use Cloudflare now, the under-attack-mode shows up when visiting the website.
So the decentralizers use the single biggest centralizing factor in recent internet history.
(Cloudflare is a great product, but it's ironic regardless)
I'm not really seeing much evidence for this other than this tweet. And the site seems to be working fine. I want to watch Tether go boom as much as the next guy, but this one might be fake news.