Just ... Scroll ... Down ... Click where it says "read more" or "show more replies"
You're human; THE most adaptable creature known. Adapt!
I'm not saying that twitter UX is perfect, or even good. I AM saying that it is usable.
The amount of stuff your brain has to filter in the form of user name, user tweet handle, additional tagged handlers, UI menus, UI buttons for replying, retweeting, liking, etc on every single code snippet makes your brain work way more than it should to read a page of text.
Just imagine if I had written this exact text in 3 separate HackerNews comments, and prepended each with a 1/ 2/ 3/ text, in addition to all the message UI, it would have been more difficult to read than a simple piece of text.