People who are really into astrology absolutely make an effort to conform to their sign, choose who to have significant relationships because of it and decide to do things based on how well it conforms to their belief about their astrological nature. That will become patently obvious to you if you spend a decent amount of time around people who are really into astrology. That's different from astrologers failing to make more nuanced predictions based on a complex chart.

Doctors throw shit at the walls pretty hard, the difference is that when they get lucky it's obvious, and when they don't, they have malpractice insurance.