It's not training though, you get thrown into the real thing immediately that decides the rest of your social time at school.

If you were encouraged and made to practice in private before, then I would agree with you. But there is no "training" in this, it's just, either you can already do it or you can't.

It would be possible to coach kids about what to say in such situations, make them prepare and practice in private, let the teacher hear the introduction before anyone else, give feedback, and then put them in front of the class. And afterwards, talk about how it went, what went well, what to improve. Does any of this happen? If no, then it's no training.