I have several forms of ID for identifying myself - driver's license, passport, military ID, etc., and they have always been all I need.
Welcome to the 21st century. Those things are fine for dealing with the 3D world. They are not sufficient when it comes to signing a legal document electronically as you must do when setting up an account for a child on-line.
Can you name just one thing that I have "excluded" myself from by not having a credit card besides adding a child account to iTunes?
You have excluded yourself from taking advantage of any service that requires a legally recognized electronic signature. Family Share is just one example.
In fact I find it offensive that I should be required to have one to prove my identity. That is like *requiring* that I provide my cable TV account number to prove my identity and not allowing me to sign up if I don't have enough channels or if I (God forbid!) don't have cable (I don't). Just silly.
You know what, I'm not offended by the fact that you don't have or want a credit card. What offends me is your absolute refusal to pay attention to and try to understand what you're being told.
There are LAWS regarding the use of on-line services by children 12 and under. The requirement to use a credit card is there because you must give parental consent for their use of the system. A debit card can not be used to sufficiently verify your identity in a way that complies with the law. A credit card can.
Stop ranting about it. That's not going to change. Go call your congressman. Until the law changes, no on-line service that allows children to use the system will be able to do things any other way.