Public or private:

Wish I could get people to broaden the definition of Constitutionally-protected "private behavior" a little bit. For example, nobody seems to have any problem with the Federal government commanding me on how wide the toilet stalls in my small business have to be.

You seem to have combined my answers to two different questions to raise your point: the one about an amendment, and the one about judicial authority. Neither of those issues are germane to the ADA, which is not an amendment to the US Constitution nor a result of judicial "activism". And if you examine the situation more closely, you'll find that it's your local municipality which enforces building codes -- the FedGov merely mandates them.

Be that as it may . . . "your" small business is public behavior, not private. Even if, for instance, it's a consulting firm rather than a retail establishment, you will want to have members of the public enter it, as clients or as employees -- or it won't be much of a business. You want to lose out on an assistant who can do everything you need, but not walk? You want to tell your gigabuck clients that they can't use your bathroom because their wheelchair won't fit through the door? (Hint: don't serve coffee during meetings.)

In my experience, all it takes for a gut understanding of the ADA is one friend (if not one's self) permanently in a wheelchair. But, we were talking about the larger picture, using the ADA as an example. I suggest that you take a similar look at what else might be "public" behavior.

Exemplary behaviors:

As for the examples of ideal behavior listed for #20, it should be noted that the current U.N. fails most of them.

Perhaps -- I won't claim to know enough about the UN as a whole to judge. But I think you understand my point: In recent memory the United States has also failed to live the role it claims. If we lead as we should, by example, others will follow.