As far as living at home, i'm in my early 20's still and live at home(though not with parents). I am more then capable of moving out(or buying rather) at any given time if the current situation explode between me and my parents.
Do I look down upon anyone for living at home? No, we all have our reasons. I choose not to so I can save up for a bigger down payment. I have a few friends that would be homeless if it wasn't for their parents.
Is there a point in time when one should move out? Its a matter of opinion. I think that when you get married, you should consider moving out and getting your own space. Even as a single guy, I am tempted to move out and be completely independent from my family. Everybody has their own opinion on this. Also, the longer I live at home, the bigger my down payment gets, and that is one huge advantage as well.
Should we judge others for living at home? Kinda like the first question, but obviously no. There is also the background in which we all come from. Being asian, I find we have the tendency to move out later in life then caucasian people do. Same could probably be said for EI people as well(not sure about blacks though). How we embrace our backgrounds also plays a big factor as to when we move out. Also how we grew up plays a role to a certain extent.
It might sound awkward to hear about someone past the age of 30 or even 40 still living at home, but in the end, its their decision. Let them deal with living at home. If everybody can get along in a single house, great, if they cant, then obviously they should move out. Lets worry about our own problems, before we start telling people theirs.