The Sith are generally just that retarded. They don't care about the Empire, just themselves and their own personal 'power.' It's no surprise they'd destroy intelligence and dessiminate the powers of the organization to where they can use it for their own PERSONAL gain. That's all they care about.
Light side Sith notwithstanding, of course.
Thats why I sided with jadus and gave him the codex they are going to rebuild sith intellgence with force user operatives and me as the leader of it but it will take time to setup.