If we focus only on high school debate for a minute (I have participated in and coached high school teams), the point is to teach kids critical thinking. When freshmen show up to debate for the first time, it might surprise you how bad they are at putting together coherent arguments. You don't get to make it to the top of the league in debate without learning critical thinking. In order to get to the "obnoxious and inane" parts of debate, you must first succeed at the point of debate (to teach critical thinking and argument). So, I'd say high school debate does a great job at what it is meant for.

Edit: Moving from a long-form rant about something that a freshman barely understands to philosophical minutia that lead to nuclear war takes a significant amount of learning. And that learning is worthwhile.

On the other hand, focusing intensely on "critical thinking and argument" is detrimental to the purported goal of debate as a civic institution - rather than a high school sport - which to educate, seek truth, and ideally come to common ground either via persuasion or compromise.

K-heavy policy is kind of the extreme opposite of that, increasingly meta arguments where no one ever has to concede even a basic model of reality to the other side. I didn't like it as a debater, and I had a dim view of it as a judge, especially from aff side.

(These frustrations had me drift towards group disco and student congress after 2.5 years in policy.)

Yes, the civic and educational goals of debate are often at odds.

I'm comfortable emphasizing the educational goals over the civic goals because I've yet to see a high school debate round weigh in on the balance of national (or even state) policy...

Not to mention the work ethic and research skills that are honed through debate and cutting cards. I am convinced that my college experience was much easier than others because I was efficient at doing research. Now that I'm in the professional world, long nights of cutting cards has changed into long hours or writing code and I'm not sure I would be able to handle my workload were it not for my debate experience

Sure, but if the intent of a game you've constructed is to turn an ordinary activity into a scored competition, accidentally instead creating some specialized thing that veers far away from the original activity is a failure (and is very likely—this is basically the construct-a-perfect-wish-for-a-genie problem). The only reliable way to counteract it is with a heavy subjective component to judging—the more objective the outcomes, the more distorted the activity will tend to become.