Like it or not, USSC precentent is law as it has been interpreted, including the interpretation of the Constitution. It is not up to a lower court to overrule the USSC which was Alito's role in the lower court rulings. And in fact if Alito had attempted to overrule precedent from the lower court he would be guilty of excercising the powers reserved for the legislature in A1 S1.
If he had attempted to "overrule" a precedent he would be applying known law to the case for which he is responsible. He is not responsible for previous court decisions.
Like it or not, the Constitution never gave the Judiciary legislative power (the word "all" in Article 1 Section 1 means something).