Thyroid is particularly awkward, because misuse of the synthetic hormone can cause the problems that mean you need synthetic hormone for the rest of your life. So you can literally take a healthy person, feed them medicine until their body breaks, and then they require the medicine forever. That's messed up. But, if you are a pro athlete, and then your doctor says you have a legit medical condition that's easily managed, but that you're not allowed to take the medication for because then you lose your livelihood, that's messed up too. Imagine the conversation - "you've got thyroid cancer. The good news is that it's localised and easily solved, you will be perfectly healthy in 6 months. The bad news is that you can't race ever again because your medication is on the banned list."
I was diagnosed with Graves disease at 28 (with a resting HR of 122!). My daughter has just been diagnosed aged 8, which makes her the 5th generation that we know of to have had thyroid issues.
PS if it were to be banned, then it's not just I can't ride with WT, but I can't get a Cat 4 BC license (or ride local TTs?).