Why are AX whoops bigger?

Probably cause there's not much going on an arena cross track other than a finish line a rhythm lane a couple of turns and the whoops. Lots more stuff on a sx track to separate people.
Just a wild guess

Yup, gotta find a way to separate these guys on those tiny tracks. Otherwise, with the small fields, huge entry lists, and short qualifying races, you would have half the top ten in points getting a DNQ every week. All it takes is a second row start and you're LCQ bound. The whoops give the fast guys the best way to make time.

Raced the AX in Charlotte in 2002 as a total noob to racing on my 125. Boy were those whoops a humbling experience

Having watched a few of the recent ax's I've wondered what it would be like to try to fill and race a stadium with arena cross obstacles. Requiring more dirt and longer lap times are obvious issues. Bring the jumps closer to the corners, more doubles in the rhythms with the occasional triple. Rather then the current set up with lots of triples and the occasional quad. Seems to me like when you slown them down over the jumps, you get more guys battling each other bar to bar.

You should've seen Louisville 2 weeks ago. The top guys could barely get through them until the end of the day. Biggest things I've ever seen.

Small tracks that are slow less likely to get hurt in the whoops make them big for separation