Western Astrology Uses a System Rather Than the Sky Regarding Planetary Alignments with Constellations

In February I discovered something that genuinely confounded me & sent me for a spin. Tropical Astrology - the main Astrology of the Western World - is not aligned with the current alignments of Planets with Constellations. 
While it seems correct regarding the Planets in relation to one another, it's a set system that doesn't account for shifts & changes over time, nor the real size of constellations. Their Chart System is man-made, not Astronomically correct.
If you look at the night sky, you'll see something different to their System. I am not claiming that Astrology of any kind is a fundamental truth, but True Sky Sidereal Astrology is the closest to what you would see in the sky, or on an App of current skies.
What does that mean regarding Western Astrology? Most of the time, they represent the Sun, Moon & Planets as being in Signs they really aren't in, in real time. Every so often a few things might happen to align, but mostly they're not in sync.
One of the most fascinating things about this for me, which I have done serious deep diving into since, is why it can seem so true to what is happening, or even to personalities or Energies in the Collective Consciousness.
That's a topic for another day, but for now - I share this because I cannot tolerate being misled or misleading others & think everyone deserves the truth in order to make up their own minds about what Spiritual systems & beliefs they choose.