Also it is not the same as repairing an Airplane. If you lose all your money you only hurt yourself and your family. (And thats the way it should be, people should loss if they are stupid with their finances.)
And yet, look at how deeply the entire world was affected. People need to be protected from themselves for the well-being of society.
Also, are you Ayn Rand or something? Your only point of argument here is that people should be given more opportunity to ruin the lives of their family at the hands of a system that has most likely willfully manipulated and taken advantage of their lack of experience (including convincing them that it was a good idea in the first place). Have some compassion.
I think in your example the banks should really have been punished more as it was their doing that caused the crisis by misleading millions of people.