I'm going to step beyond my earlier comment after further consideration and opinion that Percy definitely is a Death Wanker, that the letters were delivered by Wormtail, and that it's all a plot of Voldie's to weaken Potter. All things considered, it's more likely to end up strengthening Harry in the long run; strengthening him tremendously if some of the fallout ends up binding Hermione with both him and Ginny, the resulting combination of talent and ability would be rather scary to comtemplate having against you.