They've supported 4K for so long that I'd be surprised if they don't have enough boards capable of 1920 height.

And even then, why make it 1080 wide?

I feel like there's more going on. And maybe it's related to shorts supporting any aspect ratio up to 1:1.

But that's all assuming the article is giving an accurate picture of things in the first place. I went and pulled up the max resolutions for three random shorts: 576x1024, 1080x1920, 1080x1920. The latter two also have 608x1080 options.