Most of the questions by themselves are not stupid, it looks like the author just used them for the wrong reasons. It's more of a HR questions and as a manager he can leave it to recruiters. Many years ago I worked in HR, here's this questions as recruiters see them:
9. Trying to understand persons motivation for the job. For culture fit, for position, etc. Not a'ways 'i love it and that's my sole interest in life' is a 'good' answer. Some companies/position are looking for cold professional approach, financial interest may be interpreted as less problematic and stable. Depends.
8, 7. To see how the candidate see himself, usually entry point for more questions and soft skills evaluation. Also gives you an idea what person in front of you sees as good and bad, and if he fits the manager/team. And people do tell their real weaknesses. Surprisingly, people tell A LOT on interviews.
6. Pretty obvious - direction of development, some want to grow to be in a managing positions, some interested in tech side only, position/company may provide support for this or no.
5. Also hate it, but used to see how motivated person is and again - how he sees his strengths.
4. Asked if person really jumps from job to job or, say, stayed in company 10 years. In first case - it's suspicious and question gives the chance for candidate to explain themselves. For people who worked in one place for a long time - let's see if we are the company that provides same benefits or not.
Last three is stupid and may be illegal.
But in general - questions are just entry points and a way to start a discussion about the things you wanna know. It's not stupid if you understand why do you ask it and not looking for just an answer.
Also his solutions for those who get this questions... Being passive aggressive rarely helps. You are in conversation with someone - speak, express your frustration, explain why. Facepalm, exhale and look deeply in the eye after being asked about why do you canned so many jobs - that's a great answer I guess, explains a lot, but just understand, that you are an asshole in this situation.