I see that you've misunderstood what a material cause is. Science works because it operates mostly in the realm of efficient causation. Google Aristotle's four causes. The definition of a material cause is that it represents "that which is necessary, but not sufficient to bring something about". For instance, a man having legs is necessary for him to walk in a park, but having legs doesn't necessitate that he walks in a park. It only makes it a possible potentiality.

Astrology is probably at least one step removed from material causation which makes it even weaker (similar to risk factors). For instance you might hear an astrologer say that Mars in the 10th house is why someone got fired from their job. The efficient cause is not because of Mars, but because they did something on the job that their employer disapproved of. Another example, one can accurately surmise that at 3 am in any given location, most people are sleeping. The hour hand didn't cause the slumber, nevertheless, because life is non-random, you can sometimes extrapolate circumstances from various symbols if they behave regularly. Just be prepared for any efficient cause to override such guesses making astrological statements inaccurate.