I won't speak for experienced users as I take for granted that the bigger the experience, the smaller the possibilty of fatal mistakes
When someone goes out trying a new operating system, the very least he/she must do is be cautious.
It's like taking your car to drive down an unknown road; you wouldn't start running like crazy, would you?
You can't expect from a machine to warn you about mistakes you are going to make as a human.
When you are root, you have the complete control. The machine is defenceless. You can do anything you want.
This is how things work in Linux. This is one of the first things you learn (even after messing up your system) when you start using it.
It's up to you to use it wisely.
Do you really
believe that if Synaptic developers followed your advices, things would be safer?
And that there wouldn't be another user that "accidentally" removed some packages needed by the system, even though the complete list was in front of him?