We've recently used this exact process (to remove an authenticator), and it was glitchy/problematic even before today, with a ton of people trying to use it at once (and I assume Blizzard staff manually verifying IDs?) I suspect Blizzard's verification system has imploded.
Kind of a similar thing happened when "WoW Classic" launched. The first 24-48 hours the whole ID recovery workflow was doing similar things/broken.
It is still on them to fix it, and people are still entitled to complain, this post is more a remark on intent (purposely down Vs. just having a bad recovery system). Although "It has sucked for a while" isn't a great defense anyway.