I don't get the emphasis on testing

Testing is a huge red herring.
Since there's no way to test 330 million Americans, and no sane reason to do so if you have no symptoms, the Leftist buffoons set it up as an impossible goal, hoping you don't figure it out.
Just another way to beat up on Trump that is intellectually dishonest.

I agree, there's no way to test 330 million even *once.* Testing doesn't mean you're safe, or won't test negative in the future.