I disagree; this website is awful. If you hijack the scroll event to do something like this, instead of just... letting me scroll, you're very much going to hell.
This is not hijacking the scroll event. Look at the scrollbar. The page scrolls exactly as you'd expect according to your input method and operating system.
I know it's not technically correct, but I tend to conflate "hijacking scroll event" as both receiving a scroll event and doing something that weird or slows down my browser along with something that manipulates scrolling since they have similar effects to an end user.