Y’know, I’m a lurker in those threads, never a player, and I can’t say why I enjoy it so much, or why it doesn’t seem repetitive to me. But I get a real kick out of the threads and admire the hell out of the better ‘players’. I dunno, I’m an improv fan and a rabid Anglophile, so maybe that helps.
Or perhaps it’s simply like free-form jazz. To some it’s random, incomprehensible, unmelodic, self-indulgent noise. Others may be captivated by the spontenaeity, complexity and the give-and-take among the musicians. You don’t have to be music-challenged to be in the former category, and you aren’t more sophisticated if you’re in the latter; it’s just taste.