And why should it render all examples on one page?

They could have a static page for every property so one could link to http://cssreference.io/align-content instead of http://cssreference.io/#align-content and get just that static page. That should be pretty quick, especially with long caching of all other resources than the actual page content.

There's lots of different ways to have done it without having to do it all at once.

Or, would have complained that it was stupid to actually use an anchor tag to link to god forbid another complete page load.

Or, if they used a javascript framework to make deep links someone would have complained that they used a javascript framework for a static page, or even maybe they used the wrong JavaScript framework.

No it shouldn't. Split up large chunks if it impacts performance.

I'd probably do a full load for the text, with specifying the height for the examples inline, and then lazy-render the examples once they're visible.

The problem with this site is not that it has too much context. Just too much new and crazy styles.

Very lazy on the part of the developer to code it that way.

Thanks for the report. Hopefully the author will almost fix it.

It would require setting section heights to fixed values so you can know which section is visible and enable and disable styles for them without changing the sites height.