It's not tautological. The legislative process in which certain classes were deemed protected was not a simple declaration. I'm not going to try to look up the history and issues that led to religion being explicitly protected in the Forst Amendment, but the American Disabilities Act was passed relatively recently enough to find contemporary accounts of the debate and controversy that preceded its passage:

http://www.cnn.com/2010/LIVING/07/26/ada.history/index.html

The outlawing of discrimination against disabilities is, IMO, very humane, and it's hard to imagine something like it being sponsored by a very liberal Senator and signed by a Republican president. That said, the law has required significant costs from society. California, which I believe has stronger disability laws, still faces big debate about the cost to businesses:

http://www.sacbee.com/news/politics-government/capitol-alert...

As accepted as ADA is by the status quo, that doesn't mean that the definition of disabled, or of the costs needed to fulfill the law, are easily understood. But I do think its issues and conflicts are relatively simple compared to a law that outlawed discrimination against political beliefs.

How would that even work without getting quickly entangled with the First Amendment? Or even in implemented in everyday life. Business owners have no right whatsoever to fire someone for expressing beliefs that run profoundly counter to the business? Or to kick out a trolling customer?

> How would that even work without getting quickly entangled with the First Amendment?

You tell me, you're the one claiming it's unacceptable to refuse to do business with certain kinds of people.

> Business owners have no right whatsoever to fire someone for expressing beliefs that run profoundly counter to the business?

You mean like a Christian business being unable to refuse service to people whose activities run counter to the tenets of Christianity?

Remember, I'm not the one claiming forcing people to do business against their will is acceptable.