I got an A- in Constitutional Law at Harvard Law School. It was an intensive yearlong class taught by Charles Fried, a distinguished constitutional law expert and former Solicitor General of the United States. So, I speak with a fair degree of confidence when I say that poems inscribed on statues have no legal or precedential value in the American legal system.
That one side in a major national debate continually runs to a poetry quotation as one of their major arguments to back up their policy preferences is, frankly, ridiculous. Relying on poetry quotations is a good sign that you have a weak argument.