I don't think it is. To make that decision you have to know the cost of secret abuses. And how are you supposed to know that if they're secret?
To make the reductio ad absurdum, suppose the government's line is that a plague that becomes contagious before it becomes symptomatic is ravaging the population and everyone is being tested and the people infected are immediately taken to quarantine where they uniformly die of the plague, but in reality what's happening is that genocidal fanatics in the government are doing genetic testing and sending people to death camps.
There is no amount of undermining security that can overcome that amount of harm. But if people are assuming that the harm is dramatically less than that and are not allowed to be corrected then they can't be expected to make the right decision.
People are entitled to trust that the government won't do the sort of things that governments have historically done? This is getting dangerously close to the point of legitimizing the government of North Korea because it's nominally democratically elected.
> and also to presume that the really gross abuses will be hard to keep secret.
Isn't this directly at odds with aggressive systemic and cultural protection of secrets and imposing severe criminal penalties on whistleblowers? You're effectively arguing that the government can only get away with as much malice as they have the capacity to keep secret, and then using that as justification for bolstering the government's ability to keep secrets. That seems like it should go the other way.
Isn't that a self-fulfilling prophecy? If the government is allowed to lie to the people and keep secrets from them without oversight then the people have no way to make an informed decision, and will consequently be more inclined to make a decision favoring the government.
It's all too easy to win a public debate when everyone with the information required to refute your position is prohibited by law from disclosing it.