Fair question there.
The reasoning behind this, is its simple to code a bot to read the answered question at the top of google (or indeed other search areas). So if you put something like "what is 2+2" it will actually give you the answer, rather than you needing to click through search results.
With the second part on making it easy for users, I completely agree. However, that is going completely the other way of thinking. You don't have to put a hard physics question in order to avoid the answers being given simply by Google. As an example, if you ran a site fourpaws.com which is a site for dogs, you could put the question "What animal is this site about?" which Google cannot possibly guess as it doesn't know the context. "What is the number in the title of this site" is another good example. Both very simple for a user, but impossible for Google to know without being given more context.