Why do other provisions beside article 1 in the constitution address the legislative power?

The laws which Congress has passed on some topics are unconstitutional as outside the scope of the legislative powers granted to Congress by The Constitution. We the People did not give such powers to Congress when we ordained & established the Constitution, created the Congress, and listed its 21 enumerated powers. And these powers are not granted to Congress in any of the Amendments. If you look at The List of powers We granted to Congress, you will see that Congress’ legislative powers fall into three categories: I) International commerce and war; II) Domestically, the establishment of a uniform commercial system: weights & measures, patents & copyrights, a monetary system based on gold & silver, bankruptcy law, a limited power over interstate commerce, and mail delivery. Congress also has the power to establish lower federal courts and make rules for naturalization. III) Protection of civil and voting rights. This makes sure that the Legislative branch does not abuse their powers. I hope I helped :P

Popular sovereignty or the authority of the people referenced in the permeable of the constitution . this principle states that government power comes from the consent of the citizens.