@rchrdnsh @Netlify @letsencrypt Good question. It's because @Netlify are not themselves a domain registrar. More detail on that in the community forums:
https://community.netlify.com/t/common-issue-how-do-i-transfer-my-domain-name-to-or-away-from-netlify/186?utm_source=twitter&utm_medium=domain-reg-pnh&utm_campaign=devex
My tweets and posts live here on my own domain these days.
You can explore them here and follow me on Mastodon instead of Twitter where I'm not currently active.