> I'd probably prefer 400ms of a static screen to 400ms of animation.
The alternative here is no visual response to a click at all. I'm not okay with that, and I seriously doubt you'd be okay with it in general. Most people aren't (this has been shown). A 400ms delay after button clicks and scrolling and other interactions is an indication that your input was not received, and it feels intolerable to people today. The 400ms standard here was set 40 years ago. Today software feels completely broken if it doesn't respond with something in under 100ms, and desktop browsers typically do something within 33ms.
> the author had complete control over how much information they wanted to show
That's irrelevant. The browser does respond to your page load request instantly, with a blank page and a spinner. It doesn't break the rule.
Again, you can criticize the choices with your own opinion at a subjective level, this doesn't mean the authors aren't following their own advice. It feels like you're looking for reasons to justify not liking the page. You're free to not like the page, I won't disagree with that. What I disagree with is the reason given.
> Sure, it doesn't break rule #2 specifically, but it does break #3.
It seems like you're moving on to misunderstanding rule #3. Scrolling and clicking does not apply to Fitts' Law.
EDIT: I said scrolling doesn't apply to Fitts' law, and I meant that specifically as a reponse to, and in the context of the suggestion being made here by the parent: scrolling to find a new unknown target plus acquiring a new target, plus moving to click on the new target.
Fitts' Law has been studied on scrolling alone, for example: https://www.microsoft.com/en-us/research/wp-content/uploads/...
Extending the law to include the number of interactions is going to be tautological in the sense that if number of manual interactions is your "distance" then of course more will take longer. Including targets that are unknown is just beyond the scope of what has been studied and shown, I'm saying it is not really in the spirit of Fitts' law. https://en.wikipedia.org/wiki/Fitts%27s_law