Why is yr right wrong?
You can do just about anything on your own property, unlicensed underage drivers, drunk driving, modified cars un register able. All that is OK, so why not unlicensed pilots in unregistered aircraft as long as they are below 500' and over their own property as per powerin's post?
It is up to regulators to say what is NOT legal.
Yr right is wrong because the law says he is wrong. No matter how much you, he, or anyone else might pine for those good old AUF days and believe they still exist, as has been expressed several times here, the law says otherwise.
There is an important difference between doing things ON the land and doing things OVER the land. The right's attaching to the property vary for given circumstances (read the previous posts where I explained this).
Yes, you can drive an unregistered motor vehicle on your land and without a licence because the various State laws controlling those activities apply to the operation of vehicles on a highway.
But be very careful doing while under the influence and be particularly careful you don't hurt anyone if you are hooning around at home because those matters aren't limited to operation on a highway. Be aware also that all Crown land, in Victoria at least, is a highway for the purposes of the Road Safety Act.
Answering your question in plain English, it's because the law says you can't (at least unless you hold appropriate endorsements and are acting pursuant to them).
Kaz