I've never seen a "collaborative jam session" in programming that wasn't anything but chaos

I've been a part of very organized hackathons.

In fact, I've been to hackathons that blow away any jazz I've heard in terms of artistic merit by my judgement.

Perhaps you're making the confusion of meaning "coding" when you say programming. Coding is indeed a very rote and chaotic medium. I'd hesitate to call it art.

Programming and computer science, much like pure math, are artforms of themselves which surpass any other art humanity knows.