God has sovereign authority over all creation, not just the portion that has submitted.
Their choice. Free will is God's primary mandate for man. And the angelic host as well. The fallen and unfallen angels
made a CHOICE to either serve or rebel.
Gen 2:16
And the LORD God commanded the man, saying, Of every tree of the garden thou mayest freely eat:
Rev 21:6
And he said unto me, It is done. I am Alpha and Omega, the beginning and the end. I will give unto him that is athirst of the fountain of the water of life freely.
Rev 22:17
And the Spirit and the bride say, Come. And let him that heareth say, Come. And let him that is athirst come. And whosoever will, let him take the water of life freely.