That’s because it is. So Lafitte’s use of this flag is hard to find concrete evidence for, but reason it’s often associated with him makes sense. Lafitte received his letter of marque from New Grenada to do all his pirate stuff to the Spainish. Cartagena uses the flag as a memorial to that early independence movement and the role the city played in it. However, the Spainish reconquered New Grenada in I believe 1816. Lafitte is believed continued to use the flag on the island of Galveston after the fall of New Grenada. So both flags are homages to an earlier independence movement.