Earlier quoted context omitted.
Why react specifically? My general experience tells me that mixing presentation and logic ends badly, as well as the collective experience of the industry. We've been down this path with just about every GUI technology before but it seems we have to learn it again.
Look again; it doesn't mix presentation and (business) logic. It's all view, with the added bonus of not needing to code state transitions in the view.
Unfortunately, the example from the tweet really does: the storage and manipulation of the to-do list itself is right there, mixed in with the rendering component. I think it’s a bad example of how to write UI code using React, because while it’s concise and it works, the techniques it shows lack flexibility and don’t scale well, and they’re not how you’d actually write a larger app’s UI that renders using React.