You owe it to yourself to think critically about what you think you want out of intelligence services, being secretive is one thing, not permitting any oversight is not ok and being in direct violation of the law is also not ok.
It's not a hypothetical situation, people were using these tools to stalk women for crying out loud, you can't defend that. Those tools shouldn't have even existed in the first place, it was a flagrant violation of authority.
The reason in the UK police are charged with harsher sentences than ordinary criminals is because they have authority and an enormous capacity to do harm. So do these agencies.