14th Amendment Section 5

Because the court is the authoritative interpreter of the constitution not congress.
14th amendment section 5. 217 218 in the civil rights cases 1883 30 the supreme court interpreted section 5 narrowly stating that the legislation which congress is authorized to adopt in this behalf is not general legislation upon the rights of the citizen but corrective legislation. The congress shall have the power to enforce by appropriate legislation the provisions of this article. The congress shall have power to enforce by appropriate legislation the provisions of this article.
The section of the 14th amendment similar to sections in several other amendments is known as an enforcement provision. Amdt14 s5 1 enforcing the fourteenth amendment. The power to enforce is not the power to determine what a constitutional violation is.
The validity of the public debt of the united states authorized by law including debts incurred for payment of pensions and bounties for services in suppressing insurrection or rebellion shall not be questioned. Congress is limited under section 5 of the 14th amendment to enacting laws that prevent or remedy violations of rights already established by the supreme court.