Your three quotes are misleading. Albert Einstein said it best: 

"As far as the laws of mathematics refer to reality, they are not certain, and as far as they are certain, they do not refer to reality."

You can treat geometry either way - as referring to reality, that is, a physical theory subject to falsification, or strictly as a branch of mathematics whose certainty flows from the agreed-upon axioms which, however, may or may not correctly describe physical reality.