The culprit: https://trustarc.com

Been noticing this provider getting used more frequently on other websites. Why are so many sites using this when it makes the user experience significantly worse?

And when it finally does process (which took about 40 seconds) you get this:

"Some vendors cannot receive opt-out requests via https protocols so the processing of your opt-out request is incomplete. To complete the opt-out process, please click here to resubmit your preferences."

So there's no way to opt-out of all vendors... Am I being dumb or is this solution an utter failure in every regard.