If I want to reprogram my own FIDO2 token, I should be allowed to.

If I get your FIDO2 token and reprogram it without somehow also wiping the data on it, your problem is that I got your FIDO2 token, not that I could reprogram it without erasing it (which theoretically could perhaps be true right now)

your problem is that I got your FIDO2 token

For this exact reason, I store my cryptographic keys in a ring which I never remove from my finger.