It looks like someone has tried to reinforce the mast where the bend is. Notice the extra piece of aluminum near the bend that is not on the other side.
A sailboat mast has a lot of pressure on it and they are designed to support those loads so long as the mast is in column. Once something causes the mast to go out of column, it will collapse.
To see the effects, try this little experiment. Take a can of cold beer, drink the beer. Place the empty can on a firm flat surface, carefully place one foot on the can and then stand on it. Keep your weight directly over the can. It will support your weight. If you are young nimble and agile, take a pen bend down and tap the side of the can with the pen. The can will collapse because of the very slight deformation in the sides of the can caused by the pen. (If you are not young, nimble, and agile, have someone else tap the can).
Basically the same thing happens with a mast, so long as everything is aligned and intact the mast stays up. In the examples I've given the assumption is that the deformation happens further up the column, so that column (mast or beer can) can fold on both sides of the deformation. In your example the deformation is at the bottom of the mast and is oriented vertically not horizontally, thus it may not affect the structural integrity as much as a deformation further up the mast.
Aluminum will work harden and crack pretty quickly, so I would be cautious about hammering back into column, doing so could significantly weaken the mast and crack the aluminum.
