In high school and college I was in the debate club. I remember talking to a teacher about how he thought debate was harmful, in getting us to focus on winning the argument and convincing the judge over finding the truth. At the time I remember brushing it off: I liked debate, how could he say it was bad?

Later I came around to his point of view: debate was training in convincing people the wrong way, through verbal tricks and clever framing. Students should have been taught that the response to a point is consideration and potential acceptance, not heckling [1]. You think "why does this person disagree with me, and what do they know that I don't that informs their opinions?"

Still later I'm back to being ambivalent on debate. The skills you need to win a debate are mostly useful ones: clear thought, good examples, consideration of the audience. The focus on winning may be what it takes to keep people interested as they learn. I quit debate after freshman year of college, and I think in retrospect continuing would have helped more than hurt.

[1] "The opposing side ... is expected to taunt the other team to some degree in the rounds. Heckling is meant to be short, witty, and to the point, and can both distract and undermine the credibility of the speaking team. The dynamism of such a forum cannot be overemphasized ..." -- James Wallace in the NPDA Journal. To be fair, heckling was generally a response only to bad points, but your sense of 'bad' gets warped by the competitive framework.