Why does this decision offend you so much?
Because you're making the assumption that all people below a certain age are the same and beyond redemption.
You talk about arguing and how to do it properly, I give you my own side then.
1) We have some very good roleplayers who are younger than 16, two of whom I can confirm have gone on to lead very successful groups on the server (A certain House which I may or may not be part of and a certain faction of tribals which half the server may or may not be part of as well).
2) I've witnessed, as I'm sure most of you have, a number of very
bad roleplayers who were above the age, showing a complete lack of maturity.
I'm also going to point out here, younger minds are more creative and willing to act out that creativity if given the chance, adult minds have that filter out by society who view roleplaying as "childish".
Sally, if people are willing to go as far as to lie about their age (Who hasn't on the internet?) then surely that means they really
want to be here? Implementing an age limit will only increase the number of liars who come here and turn away potentially great players.
Sally, I understand that some people are beyond hope and should be kicked/banned as soon as possible because they'd just ruin things otherwise.... but we should not be denying younger people the chance to express their creativity.
Encourage them to roleplay better,
teach them when they've done something wrong, don't punish them!
To quote the intro to Halo, "children's minds are more accepting of indoctrination". Adult minds are not.