Well, that's because most people in this Horoscopes section don't understand Astrology in a deep way. They only know about the basics of Astrology. All they know is the sun sign. That's why they often criticize and judge about just anyone based on his/her sun sign, which is not true, like you just claimed. Because we must take a closer look at our entire birth charts in order to determine who we really are. Our sun signs aren't everything, we also have to consider about our moon signs, ascendants, descendants, mars signs, venus signs, etc. Also, our astrological placements/aspects often determine what type of personalities we really have, all of these things in astrology aren't explained in most places, which is why most people don't have a clue about them. That's why it's very important to learn something completely, not just the very basics of something on the exterior surface of it. Knowledge isn't gained in one day. You have to study harder in order to learn an entire subject.