I don't think a child should lose love whatever s/he is or does. In a healthy family that is not happening. Unfortunately that might not have been the case with many of us. I'm sorry if that has been the case with you.

In an adult world, people do change, feelings change, sometimes people just drift apart, sometimes something too malicious or abusive happens that makes wagging the tail impossible. Luckily there also is love that stays and only gets better with age.