"hydrazine is more or less like hydrogen peroxide. "
Danny, your too funny

hehe. from the conspiracy theorist himself!
from wiki:
Related compounds
hydrogen peroxide
ammonia
monomethylhydrazine
dimethylhydrazine
phenylhydrazine
i guess what im saying is that just reading that list of hazards gives you no real feeling for how hazardous it is. for instance here is an even longer list of hazardous effects of another compound.
i still say that radioactive materials on board would be greater cause for concern...
edit: oh, and at least i know what inertia is 
Well, if you read the MSDS sheets on common things like sugar, salt, water, etc., it will list some really nasty reactions and health problems. This is because they legally HAVE TO. It's like the inserts you see on common drugs like tylenol or pepto bismol. If there is ANY chance of something serious happening, it MUST be explained otherwise the sue-happy society we live in will make a fortune in pointless lawsuits. So many descriptions of chemical compounds are a bit exaggerated not because they are true, but because they are required to.
With regards to radioactive material, it is possible that the satellite has a plutonium battery in there only because it has such a very long useful life span. The thing is, those batteries contain so very little radioactive material because of the fact that they are faily efficient at creating the energy needed by the satellite. Most of the energy it needs comes from the solar panels satellites have. If the plutonium cell were to be vaporized in the freefall to earth, the equivalent would be like putting a mL of arsenic into the pacific ocean. The dilution renders it harmless. E.G. below normal background levels.