But if we challenge our opinions, we can make better decisions. If we challenge and they hold, we are more confident in them. If we challenge and they don't hold, maybe there's a better idea to explore.
In short, what I believe is: you can aim for the truth, and you will be better for it, but you will never reach it.
Tame example: say that we know that objectively 100% of the time that browsing Facebook leads to depression. Okay... what do we do with this? Do we force facebook to change, maybe even ban it from a country? do we strongly regulate people using Facebook? Maybe only regulate minors? How does that information affect Instagram or any other Meta product? One "truth" doesn't answer these questions.
Second of all: debate is ultimately communication, and communication is about being able to express your own thoughts, often while trying to appeal to other person's thoughts. These core factors of society are important no matter the topic. It should also ideally teach one to consider multiple points of view and make for a more well rounded understanding on comlpex issues, but well... here's the article talking about modern debate.
On the other hand they were talking about religious training, and religions are pretty clear that they do teach (some sort) of truth.
The goal here isn't to find truth, because sometimes the truth doesn't exist. It's to understand and be ready to counter-argue conflicting stances when necessary. Knowing what your opponent will say lets you better strengthen your own argument.