Me!! Because I don't really believe in astrology and its validity.
Well said, Annabelle - nor does anyone else who is really honest with themselves, believe in astrology these days.
Computerised horoscopes put paid to all the nonsense of 'You must have got your maths wrong when you erected the horoscope' when things didn't work out.
Once it all became computerized and unquestionably measurable, astrological prediction turned to dust.
Astrologers with the gift of the gab, as with Tarot, could manipulate the material in any horoscope - using house cusps, rulers, etc., to get any chart to say whatever they wanted to, in retrospect.
I often watched one of my astrology teachers do this, but ultimately it's meaningless, apart from giving the owner of the chart their five minutes in the sun at a price.
An accurate future prediction, apart from randomly or as the result of a reader's shrewd intuition, is impossible, despite the self-delusions of some sad souls.
Nevertheless, a lot of very good minds put much effort into creating astrology, and the complexity and mathematics of astrology can be fascinating for a while.