The word "only" makes this sentence completely wrong.
In startup terms it's like saying that to make a successful product you need only make something useful and put up a web page offering it for sale. It would be great if it was that simple!
To show context, my entire sentence was: Projects can maintain fairness without specifically targeting a demographic, they need only be open to everyone and never turn someone down simply because of an attribute they cannot change [gender, sexual orientation, race, religion, height, etc].
So by "only" being open to everyone, I assert that projects can maintain fairness. How is this incorrect? I never said the project would be successful, you falsely added that using your metaphor. Is there some other magic bullet for making a project fair? Do we need to inject some discrimination and close-mindedness into it?
We don't need to inject discrimination and close-mindedness, but we do need to counteract it. That means we can't just passively "be open".