To observe the oceans move by the power of the moon, then declare that people are unaffected, is folly.
To know that global conditions vary by the phase of the moon and claim it has no effect on people, is folly.
So wherefrom came the idea that astrology is sorcery? It is a tribute to the dawn of the Aquarian Age, we don't execute astrologers for sorcery.
So where did this link come from in the carefully cultivated Christian mind? A story might explain it: In a large village, long ago and far away, there was a council of elders which pretended to wisdom.
They were very jealous of a man who was truly wise and lived alone on the outskirts of town.
Being wise men of leisure they loved to spy upon the wizard.
The council met weekly and discussed their wizard observations.
In time the council decided the wizard was getting too much attention and probably offending God in the process.
The wizard was executed and the people lived happily ever after.
To this very day, all the descendents of all the people of that village, know that wise men are wizards and ought to be put to death, as they did in Russia and China last century.
Today, when an all knowing Christian tells me astrology and numerology are sorcery, I know who his/her parents were.