Why am I breaking a ridiculous number of spokes?
Generally, repeated issues with broken spokes indicates either damage to the rim, meaning that the metal hoop of the rim is physically bent while under no tension, or that the spokes are at the end of their fatigue life.
Any wheel has an expected use life, and usually, you will wear a track in the aluminum rim from braking forces before the fatigue life of the stainless steel spoke becomes an issue. However, if the rim is damaged, as referenced in your previous question, then the tension of the wheel cannot be evenly consistent, because some spokes must be tighter than others in order to hold the rim true and straight. If our wheel is unevenly tensioned, it allows a far greater amount of movement of each spoke during the revolution of a wheel, and this stresses the spokes beyond their designed strength. And you break more spokes.
If the rim is not bent, the same issue applies, except it is smaller movement of the spokes over a far greater period of time which has pushed the spoke beyond its useful life.