The job of scientists is to go through the list of all possible theories and to eliminate as many as possible, or, as Popper said, to “falsify” them.
I don't think this is Popper's premise. His point isn't "go around falsifying as a hobby." It's that if you care about truth, you need to check the possible theories, and that checking has to be adversarial and have some real possibility of disproving it.
