This applies to many different visas. The point is to ensure you are actually employed and not just here to subsist off of social services or working for illegal enterprises (i.e. organized crime). You can change jobs but the new employer must agree to sponsor you. Visas are not permanent residencies or citizenship. If you just want to tour the country or take university classes, get a tourist or student visa. If you did all the work to prove your "extraordinary abilities", you should be putting them to use. And yes, perhaps freelance work should be eligible for employment status but I feel that can be accomplished through some creative structuring of a tiny contracting firm.

I can easily compare an O-1 visa to being accepted to a prestigious university. You proved you are smart and talented enough to be there but if you don't actually put in the work (get good grades/stay employed), you get kicked out so that someone else just as smart and talented can take your place.

only in America. in their home country, they're allowed to work freely.

> Nice, just like in the good old days with serfs and feudal lords.

I can't tell if you're being sarcastic or not.

Serfs were largely agricultural workers bound under the feudal system to work on their lord's estate. Foreign workers aren't serfs. They're not bound to a particular estate, nor do they typically execute agricultural work. They have the right to collectively bargain their salary, working conditions, and benefits. They are free to resign their position and leave the country.

The O-1 visa is a temporary worker visa. The expectation is that folks on a temporary work visa work temporarily. That is, there is no intent to immigrate.

You are also not bound to a particular employer. You're only bound to that employer on that visa instance. You can, if you like, apply for another O-1 visa sponsored by a different employer.

There are, in some cases, restrictions on work even for folks that have the right to work and live in the US. For example, if company A contracts out work to company B, it is often not permitted for company A to offer workers at company B full-time positions at company A because of the existence of the contract. If someone freelances for company A they often can't also hold full-time positions at a competitor to company A. Is this feudalism? Of course not.

TL;DR: Freedom to work does not imply or mean, "I can do whatever work I want for whoever I want." There are rules, regulations and laws present for a reason. We can debate whether or not those reasons exist in good faith, but equating "I can only work for one specific employer on a temporary work visa" to serfdom is awfully disingenuous, in my opinion.