Earlier quoted context omitted.
Certainly. However, there are many things where people are expected to reach agreement. It's not clear that this has to be the matter on which they learn it. Indeed, considering the harm that can result, it's probably better if they learn to reach agreement on some other matter first.
Can you elaborate? There is potential risk of harm resulting for many other areas of personal developments as well.
Faults in agreement include parties generating agreement that doesn't reflect their values and/or desires, and the illusion of agreement by one or both parties.
While there is potential risk of harm in many other areas of development - including other areas of agreement - the stakes are not usually so high. Getting an illusion of agreement for what movie to see, what restaurant to eat at, or (at a younger age) what toy to play with, will tend to have less severe consequences than an illusion of agreement over whether to sleep with someone.
It is not clear that someone gains the most from risking the most. Why is an agreement over sex the defining developmental step of the skill? Especially since there are so many easy ways to reach such an agreement if you're not particularly picky. (I believe the classical example is, 'You give me money and I sleep with you.')