You’d expect following a quickly-moving thing with their eyes to make someone dizzy.
I more often get dizzy by having moving things in my peripheral vision while I focus on something that’s still– e.g. reading text with moving gifs/video in the sidebar next to it, watching something mostly-stationary on video while a text crawl moves across the bottom of the screen.
I know I use my peripheral vision to ground myself and know where I am. That’s why I don’t like looking at a bright computer screen in a dark room– because when my eyes are adjusted to the bright screen, I can’t see any details in the background.
I guess the same thing applies here– my peripheral vision gives me my sense of what’s stationary, so moving things in it mess me up.