I don't think you necessarily mean to, but some of your posts come across as a little entitled and bitter, Emarc.
Regardless, it's not us who you need to convince. We don't set the rules.
But to
try and explain it from their point of view, they want students who are the most open to the "transformative" power of HBS both in terms of approach to thinking and career potential. Older more jaded students may be less open to that. Harvard also wants students who will make an impact, and the earlier they can set a person on the career track that gets them into very high level positions, the more likely they are to get there.
Could be wrong on that, but just for your edification, I've tried to rationalize it.
Still, I don't think 27 is out of their wheelhouse.