I believe one of your legal rights is you can't be compelled to sign away your legal rights in exchange for something like a chance at employment.
So, you aren't signing away your legal rights in exchange for a chance at the job, you get that either way. You are agreeing not to exercise some legal rights in exchange for feedback, not in exchange for your application to be considered.
Imagine you check the box, you don't get the job, and your feedback turns out to be "You're a man and we don't like to hire men." You have no recourse because you agreed not to sue.
You can argue that that's obviously illegal hiring criteria and you should be able to sue anyway, but then you're back to square one.