With all of the objections to George III in the Decloaration of Independence, our Founding Fathers could scarcely imagine the satanic and murderous evil of the Demonicrat political party seeking to destroy the Constitution of the United States.
The Constitution of the United States grants Congress the authority to set the size of the Supreme Court through legislation.
Therefore, a Bill (presuming it becomes a law) expanding the size of the Court (or reducing it) could hardly be said to be "destroying the Constitution", since such a law would be perfectly Constitutional.