Joyce E.A. Russell :
If the company has fewer than 15 employees, then they are not covered by the EEOC. So, technically, he is right about this. But, the real question is why would he even care about asking you this? And would you want to work at a firm that is pressing you on this topic?
I tell applicants that when you get some of these "questionable" requests, that you might want to nicely deflect by asking them a question. For example, if they ask you to put down your age or years of graduations, you can say" If you are asking me to verify that I completed school and got my degrees, I am happy to get the schools to send my transcripts or to let you know I completed the programs." Likewise, if they ask about your parental status, you could say "If you are asking if I can travel or work on weekends or nights, I am able to do that." The reason I suggest this is that many applicants feel worried about confronting potential employers (since they want a job), yet by redirecting the question, they feel better about saying something.
You are right to be concerned. Generally, we would not advocate that an employer ask about your graduation dates or age, regardless of the size of the firm. I also agree with your attempt to leave that material blank on the form since it is really not relevant to the job, unless, of course, it is a job where there is an age mandate (e.g., flying, driving, etc.), and they have a legitimate reason for asking. Sadly, some smaller sized firms ask all sorts of things because they can get away with it, and this turns off potential employees who could bring a lot of value to the firm.