Of course, just about any fool knows there are about as many present-day and historical variations of astrology as there are cultures on this planet!

DUH ...

Just as there are seemingly endless variations of religious beliefs and practices, musical instruments and genres, social customs, clothing styles, child-rearing customs, marriage laws, death rituals, culinary habits, war tools and techniques, sexual attitudes and practices etc etc etc. Do you think these cultural differences render any or all of these things 'invalid'? Or is it just astrology that's invalid, in your worldview?