Why can't government employees be fired?

Seriously, why?

If an employee at any business anywhere in the country was caught:
Lying,
Cheating,
Stealing,
Mis-managing,
Wasting oodles of money or
All-out failing at what they are supposed to do at their job,

That person would be: FIRED WITHOUT PAY.

They would be fired and would have to go find another job.  They would also have to stop lying, cheating, etc...

But, if you work for the government, man, it is a free for all.  You can waste other people's money like crazy and you will probably be promoted.

You can be corrupt, you can lie, cheat and steal.  You can even let people die and, "Oh, well" shrug "That is too bad."  A government employee would never be fired and even if they were put on leave, they would be paid, forever.

Does anyone else understand this?  If someone could explain it to me, I would be thrilled.