I would think by far it’s for crew safety.

Recovery due to an in-flight abort would be difficult in rough seas and weather if they had to be plucked out of the Atlantic.

The aerostructure of the falcon 9 can only withstand so much side loading due to aerodynamic forces and wind before exceeding the operational limits of the rocket (body to keep it all from breaking apart, and the engines working hard to keep them on the correct trajectory).