the use of rob with cars

I am wondering why you can say "I robbed a bank and stole the money..." or "I robbed a post office..." or "The bus was robbed while the passengers were at the restaurant"

But it sounds extremely strange to say:

"Last night, my car was robbed and they took my stereo, my money and all of my CDs."

The more common way to express that would be my car was broken into but why can't you say my car was robbed or my purse was robbed"?

The major difference between the verbs steal and rob -- which can both refer to the same event --
is that the object of steal is the thing stolen, but the object of rob is the owner of the thing stolen.
Thus

• He stole $3,000/a Maserati/everything.
• He robbed the bank/Harry/everybody.

but not

• *He robbed $3,000/a Maserati/everything.
• *He stole the bank/Harry/everybody.

I think part of the reason that the ideas of "robbing a bank" or a "train robbery" make sense is the implication that the people inside (or the organization itself) are the real victims of the theft. Corporations are often thought of as entities (e.g. Google says...) but I don't think that most people think of cars as living entities in the same way. I think when a container or similar inanimate object is stolen from, it is "burgled" rather than "robbed."