No. The user might use his control to make his computer less secure. Then it does't have security. And in real life, most user do exactly this when they have the option easily available. Most viruses spread through user control. Users choose to run programs which are viruses. Users choose to not upgrade their insecure software. Those are pretty much the main ways viruses spread.
You start off by saying "The user might use his control to make his computer less secure" which is true. But just two sentences later you claim "users choose to not upgrade their insecure software" which is obviously false. They might but the might not.
I could argue the same way and claim that removing user choice might make the computer less secure e.g. by forcing updates to an insecure version, installing backdoors etc. In the real world, this is exactly what happens. Therefore removing user control makes computers less secure. Now do you agree or do you think that my argument is deeply flawed?