It's not just you. The JavaScript is doing something to mess with user initiated scrolling. It's also killing two-finger-left-swipe on my trackpad to go back. Disabling JavaScript makes the site work fine and doesn't seem to take away any obvious functionality.
This kind of thing is very annoying. If you want to present a completely new scrolling experience (like those sites where they are essentially a vertical slideshow and attempting to scroll changes the slide), that's one thing.
On those sites it is quickly apparent that scrolling does not work normally AND it is quickly apparent what the site is doing differently so I can quickly adapt.
Sites like this where the scrolling is just being tweaked instead of being replaced wholesale are much more annoying. Something is wrong but it is not immediately apparent just what is wrong.
Don't do this.