Why does Freemasonry have such odd symbolism like the skull?

The skull and bones, or specifically the skull (or deaths head) is actually a symbol to remind us of death, as it is the ultimate equalizer of man as none can avoid its eventuality. This is more a means to remind us that no matter our station in life, rich or poor, we are all subject to the same fate, and that our goal should be to make this world better for everyone.

The course of that meaning is that all Masons should always strive for our noble endeavors, namely brotherly love, relief, and truth.