Light and darkness
One different analogistic way to consider this topic is in light being the manifestation of primacy in material form and darkness being its absence. Darkness considered to be substantive leads to much of the commonly held notions concerning the origins, actions and social/personel placment of negativity and associated behavior. The implications of considering in this way would mean that as u noted for one, light would be unaffected by darkness and would actually diminish darkness to the degree of its intensity/power/purity.
Rather than thinking that our interactions are positive or negative attraction activites we might see them as more of a puzzle pieces relationship, and how these confused irregular multiangulared energies are unavoidable compared, tested for fit and finally found to be syncable or not. Ready for harmonius dissposition or not. An oftentimes predestined and particular set of groupings but evan being neutral or situationally purposed, component/elementally modifying at times. So that on some future track the singularity of actualized design might be enjoyed.
Since we are living fairly unconscious lives, evidenced by the uncontrolled, aggresive and reactive mind states we often inhabit, the more we think on such things the more we create posibilites which tho seemingly have evidence are on deeper analysis found to be often erroneous because of incorrect suppositions about the basic constituant makeup of reality.
Part of our delima in learning how to live healthily, affectivly, happily, is at first we are usually taught, and we thus choose, to think on and about our expereinces. Along with that we decide to consider a social acceptation of a good and a bad. So that we struggle more and unneedfully with seeming or real disharmony, we fight externally and internally, to create a reality that matches some mental conception.
The more we think and consult with ideas and mental conceptions as foundational parameters, the more liable we are to be prone to hypotheses which are based on a lack of experiential evidence.
Tho questioning, analysing, considering are elemental, and can lead to realization. Actual living out our experiences and w all that that entails is the proof and product we find in the calculus of our relationship with difficulty and in that more appropriately sequenced formula we find the lessning of thought derivities and the increase of perceptual awareness, which answers and satisfies the suffering confusion to a level of knowing which is not err to disscursive's dualistic orientation.
I hope this diatribe is clear. Along with your other topics u asked the particularly common question of why do the "good" suffer. In the work of the perfection of our characters, challange plays an important role and if u appreciate my drift in seeing suffering as a missrepresention of reality by learned social dynamics, the answer starts to be revealed, along with the recourse being found in learning to live experientially the complete and real, true power (which includes pain) found in each moment. Thus catharsizing ourselves into an awareness which incorporates more of life's confusion in a healthy, less troubling, non reactive, way.