When Minecraft compares KeyBindings, it compares their keyCategorys with a map hardcoded inside KeyBinding.java, which is private. This make it hard to add KeyBindings for mod developer, because most mods put their KeyBindings under their mod's category.
I suggest Rift to supply a method to add key category, or even automaticly add key categorys because it is a reasonable part of KeyBindingAdder function.