Why did they ask that question in the interview?

Here is an article that I found that I thought was worth looking at. The title is a little too slighted for me but you should be aware of what HR folks can and cannot ask you in your interview.

I wouldn't suggest being too closed off in the interview despite this. Anyway, click here to read the article.

Conduct Job Warfare Like George W. Bush.

Yes. Looking for a job and warfare can be related. You need contacts: people. And you need contacts: shots that hit their intended target. But where I'm going with this is preemptive strikes.

How many HR people do you know?

That's not a rhetorical question. Count 'em up! Then contact them and stay in touch. This is important whether you're currently looking for a job or happily employed. In fact, if you preemptively reach out and stay in touch with HR folks the better position you'll be in when you are looking for a job.

Go the extra mile and seek out HR folks in companies within your industry or the industry you would like to be in. Make a friend and stay in touch in case something changes for you in the future. They may even reach out to you at an unexpected time. So the lesson here is to be preemptive in your job search.