>Everything loaded after a 1 second delay, so I'm assuming that that's how they got around ublock.

I'm not aware of any adblocker that disables blocking a few seconds after page load.

>Crazy that I saw some no-name site like this getting around my adblockers before I've seen any major site do it so nimbly. Congrats, I guess.

Not really surprising at all. Adblockers operate on blacklists, and if your site is small enough you might be able to fly under the radar and not get added to those lists.