EPendragon elaborate on this. It seems like you understand the shell enough to use it productively and customize it to be how you like it. The screenshot this quote is talking about looks like a shell? In what way is it dreadful, and in what way do your customizations make it not dreadful?
For example, it seems like a valid criticism that shells are not very discoverable and a prompt and blinking cursor can be intimidating to a noob, and that surely applies to tmux as well. But then changing the shortcuts doesn't really address that, does it?
To me it seems your article is either saying, "tmux is a pig, and here's me putting some lipstick on it," :) or the problems are not insurmountable, and the solutions are nice but not life-changing.
It's great that you like it better now, and we're all having fun chatting around it about how we configure our tools here on the Hacker News :) But I don't see why it's "dreadful". It's just.. computers, no? Tmux seems no more gatekeepy than any other aspect of computers. And I say this as someone who stopped using tmux a few years ago after getting super annoyed with it.