"Robbery" is often used when force isn't involved. If the object is stolen while you're nearby, people will often refer to it as a robbery. Outfielders rob batters of home runs all the time.
The word "rob" is particularly useful because lets the victim be used as the direct object. If you want to emphasize RMS as a victim of personal theft, that's the verb to use.
The words have a specific technical meaning in this case, so it's important to use them correctly. A robbery and a simple theft are treated very differently under the law. Prescriptive grammar is the only way to go when you're dealing with a technical system built out of ordinary language, like law or programming.
I think that's fine in general. However, in this case, "robbery" is basically being used as a technical legal term describing a particular crime. It's a little bit like calling every laptop a macbook (except there's no trademarks involved).
The word "rob" is particularly useful because lets the victim be used as the direct object. If you want to emphasize RMS as a victim of personal theft, that's the verb to use.