Because the press is TELLING you that the banks are failing.
What the banks are asking for is the ability to apply a bit more logic to the valuation of their assets than the blind panic of the market..which you seem to be participating in.
One of the principle necessities of the banking system (not just ours) is confidence. Its how the money multiplier works. Banks take everyone's assets, have a certain retention limit, and loan out the rest. So, if 10 people run on the bank...they are only holding enough hard asset to pay one of them back. That does NOT mean the system is broken. That means the system is working as intended.
What the mass writedown of assets did was create a liquidity crisis. Because they had less assets, they had no money to loan. Not loaning money created, in some cases, an inability for existing loans to be be paid. TARP funds are, IIUnderstandC being used to bolster assets in order to create that liquidity. Allowing assets to be valued in a more logical fashion than a panicked market will also help create more liquidity.