I really wish HN supported images so I could reply to this comment with the boy-crashes-bike-after-putting-a-stick-through-the-wheel meme it so richly deserves.
Its interesting that most comments appear to be running it on their phones. I wonder if most links on HN are viewed on phones primarily? Phones are generally newer than laptops and most developers will have the latest technology.
Developers especially with tech demos like this, use the latest tech to develop and don't care about supporting older devices. This attitude can sometimes bleed over into their work where they should care for users using older machines, but its expected for a look-at-the-shiny demonstration to other techies using top of the range hardware.
( I am seeing the same laggy effects on an older linux + firefox laptop with integrated graphics, unsurprisingly )