Hi,
Blood Golem currently casts Sanguine Orb from extremely far away (probably the maximum possible distance), which means that the very very slow projectile will almost always either miss, or barely graze the target and fade away.
It also makes the tankiest Golem variant stay far away from the action for quite a while (the cast animation is not very fast and stops the Golem) rather than rushing in first like one would expect.