As a youth, fantasy shaped my concept of white and black magick. White magick was healing, black magick was harmful, grey magick had a balance of the two. As I sought to learn more of the nature of magicks, I found myself looking to nature itself. I considered the most powerful "white" and the most powerful "black" within our existence. A star is the most powerful white, a black hole is the most powerful "black". But I noticed a trend, a star pushes its light outward, a black hole pulls light inward. My experience with this would suggest that (magickly speaking), pushing a curse on someone is indeed white magick, and pulling sickness from a person is indeed black magick. Again, fantasy has failed me. But one that truely embraces and studies true magicks can understand this concept, maybe only just now as my words are being read. "Quasar" is my subject title, so I'll explain. A quasar is when a black hole pulls light from a nearby star. It resembles a yin/yang symbol. It reminds me that every push has a pull and vice versa. Magick is not good or evil. Black or white magick only tells you the direction that it's travelling. So to attempt to move magicks in only one direction is restricting. It seems that all witches, occultist, druids, and any other that claim access to magicks are truely a quasar seeking which direction to move.
If I am not mistaken a Quasar is the term given to the complete structure of a light that is seen (which and is) moving billions of light years away. [This comes from the perspective of someone seeing it perpendicular to him/her] This light comes from what is called the accretion disk [spiral shape] that is surrounding a black hole. Which in its size can gravitate small galaxies and even a star towards itself.
While a black hole is a huge ball containing massive energy that no light escapes from it. I believe it is the energy that is being gravitated towards it and not the light itself (based on what you illustrated as an example) [The part you explained about the process is the effect, in which something that you see that you define as having light, when it is near a black hole, it gravitates towards the black mass of energy] making it disappear. In reality, it will explode! ("That is goodbye to the star.")
Moral on the other hand greatly differs per individual. What is right and wrong can be a very subjective topic. [What you may see as something that is in itself ("intention") good, may be bad for other people]
And just to be clear: "Magic has no color." There are consequences for every action you make. If you are not careful about what you do the effects can back fire on you. (It isn't about direction)