To understand just how fast these kids are talking, spend a few seconds watching a debate video (this was the first thing that came up when I searched "policy debate" on Youtube, and it's consistent with my own experiences): https://www.youtube.com/watch?v=e4MzZ_WS_Ww#t=1m45s
Debaters started formulating outlandish arguments. The more apocalyptic the outcome the better, with little care for the argument’s probability or real-world application. “A new retirement program will trigger a nuclear war.” “Prison overcrowding would cause the destruction of the ozone layer.” High school debate had come to this.
If anyone thinks this is hyperbolic, I can assure you from my 4 years of experience on the California high school debate circuit during the 00's it is not. The premise of the competition, that "failing to respond to an argument means you concede the argument" means that it doesn't matter whether you have effective talking points; simply that you have talking points of any sort. Volume over effectiveness, speed over eloquence.
However, there was always a stark difference between local debate competitions and invitational or state-level competitions--at higher-level competitions, many judges are former participants, and will take notes on the "flow" of the debate, which allows them to confirm, "Yes, the affirmative side made ten arguments, and the negation side only responded to nine of them," turning into a game of scoring points.
Converesly, at many local/league competitions (which might include volunteer judges with no debate experience, e.g. parents of kids at the schools participating, or faculty at the school hosting the event), many judges lack both the familiarity and the inclination to effectively recognize teams that have "won" based on this technicality, and weight was often given to students who were able to talk "like real people" at a reasonable pace that the judges were able to follow. The "negative" side of this is that sometimes debates were decided by who was a better orator or came across as more charismatic rather than which side had the better logical argument (though you could make an argument that there's value in that as well). Granted, this is based on my experience in the Yosemite Forensics League; I'm sure the tenor at "local" competitions varies on a league-to-league basis, and YAL does include a lot of California's more "rural" counties (think Bakersfield, not San Jose).
I think my experience does get toward a different point, which is that the kind of competition you see at high levels may not be reflective of what some (or even most) kids experience when they simply go to tournaments several Saturdays out of the year and never advance to a larger state tournament. If you're going to a prep school that is renowned for having a champion debate team, then sure, you're going to get fast-talking spreading, but for some kids who aren't hyper-competitive, never advance (and are okay with that), there's still plenty to get out of the program (and arguably more to be gained from a personal enrichment standpoint, even if there's no accolades). That being said, my best experiences with the National Forensics League programs were more on the "individual events" (which features events explicitly score based on oratory ability, e.g. "dramatic interpretation" or "original oratory"), rather than the debate side of things. (At my school, both were coached under the same umbrella program.)