i would think it's both, horrible security situation on desktop machines plus old attitude to build websites usually not supported in modern browsers (mostly IE only), but in general Chinese websites are extremely heavy on browser, not optimized with very dense layout

don't get me started on official monopoly railways website ​for selling tickets, straight outta 90s

though TBH Amazon website is also straight from 90s and it's hard to find even in China major shipping site which would look more dated