I kind of have to sympathize with this commenter. Although I don't agree that federated social media is very difficult, it is definitely more confusing than normal social media. I would consider myself to be more technical than the majority of people, and even I had a confusing time switching from traditional social media to federated platforms.
If the goal is to have these platforms become more mainstream (which I would love to see personally), then there does need to be simpler ways to use them, or at least better, more concise explanations.
The thundermail domains are thundermail.com and tb.pro. I'm curious to see how they will compare to the top privacy-respecting email providers today, and how they think they will "provid[e] a better service than the other providers out there," which would include Protonmail, Tutanota, etc.