This is going to sound mean, and I don't mean it to be that way, but frankly, no, the archive is not "for all of us". It is my understanding that the entire premise of the project is to create a place in which controversial content can be safely and securely hosted in a manner that is very unlikely to result in anyone getting sued, served with a C&D letter, or publicly profiled as a pedophile or incest-promoter. This necessarily means greatly restricting or prohibiting access to minors -- as JKR's lawyers will send C&D letters to anyone that doesn't have age verification and password protection.

People who are underage can go to one of the many many already-existing archives to read fiction that is appropriate for their age. It's a big internet. There are lots of places for underage fen to congregate. This archive will be useless if we can't ensure that minors cannot access the material -- why would we even bother?? Five minutes after we get it up, we'll have to shut it down.

Yes, this means a lot of hoops. If people don't like it, then they don't have to participate. They can stay with LJ and get their journals deleted, lose their content, and be profiled by vigilante groups as promoting pedophilia and incest.