Actually, the age limit is chronological, and it is set to be a benchmark for the squad as a minimum requirement. We need to set the limit somewhere, and it seems to be working out for us.
It does not mean that those who are over 18 are automatic; they can be dropped for their immaturity.
As for the WWJD quote, please don't trivialize it by incorporating it into such a discussion. It is not about being 'nice' or 'friendly.' The age restriction is a yardstick, and we'll be sticking to it.
Cheers, and I hope that you can find a squad who'll take you, StealthOwl, or simply keep flying online (or offline, as you prefer.)
As mentioned, please join us on Saturdays for UbiZoo COOP's.