It's just another way to loot in a game that is all about looting. Sc doesn't put out a manual stating you must use this type of army to steal this type of loot from other players.
besides maybe they were dropping trophies to go hide in even lower leagues from guys that can steal all their loot and instead of dropping their king on you they dropped their spells......you just never know why.
i zap. I will continue to zap. It's my only recourse in revenge against guys that drop trophies in order to attack lower leveled guys. So they put the hurt on me and I keep lightning spells handy to pinch them back. They happy, then they not so happy. I on the other hand feel quit pleased with myself and will continue to do so.

Many times I don't even bother smashing their exposed th just because I don't like them playing in my pond. If I'm regular raiding I don't do that, but revenge I will always do it.