Earlier quoted context omitted.
The fact that justify-content and align-items changes based on horizontal or vertical is useful for many reasons: toolbars that can become vertical or horizontal per user customization, or vertical writing-direction, for example.
I'm saying the syntax is terrible. The functionality is limited. Why is one 'content' and another 'items'? If you want horizontal and vertical alignment to switch places when you change directions, then you can have a flag that does that for you. For example I have X | X | X - a horizontal layout. I want it left-aligned horizontally and top-aligned vertically. (Top-left corner) and I make it work with the current fle…
Switching orientation is a basic requirement for the whole idea of flexible boxes in CSS. From MDN [0]:
> The flexbox layout algorithm is direction-agnostic as opposed to the block layout, which is vertically-biased, or the inline layout, which is horizontally-biased. While the block layout works well for pages, it lacks sufficient definition to support application components that have to change orientation, resize, stretch, or shrink as the user agent changes, flips from vertical to horizontal, and so forth.
[0]: https://developer.mozilla.org/en-US/docs/Web/Guide/CSS/Flexi...