You make a good point - one that I've seen many times before. It's true that any social media platform can ban you or even disappear at any time.

But so can the platform you use to build and manage your list. I believe you use ConvertKit? What's to stop you getting a spam strike from them or ConvertKit even disappearing altogether.

You could argue that you can download the emails of all your subscribers, and you absolutely should do that, but you can download your email subscribers from Medium, too.

I'm not knocking your advice, just trying to clarify it in my own mind.