Answer: Sediments become well sorted through erosion, and poorly sorted through natural disasters/cataclysmic events.
Step-by-step explanation: When something, say a massive pillar of rock erodes, then the many different layers of sediment become easily visible over time. Each different type of sediment and rock is easily visible, like the layers on a cake. This is due to erosion by wind or water, which slowly scrapes away the top layers and reveals what is underneath.
On the other hand, when a natural disaster or cataclysmic event occurs, these carefully separated layers are mixed and blended together in a poorly sorted fashion. Using our cake analogy, well sorted sediments by erosion would be equivalent to cutting a layered cake, while poorly sorted sediments by cataclysm would be equivalent to taking a hammer and smashing the cake, which would sloppily mix layers of sediment together.
The key difference between poorly sorted sediments and well sorted sediments is time. When sediments are well sorted, it is through erosion by wind and water, which is a lengthy and gradual process. However, when sediments are poorly sorted, it is through disruptive events such as natural disasters.
I didn't really organize my ideas in the best order, but I hope this makes sense and helps! Have a great day!