Asking for "Statement of Purpose" when applied for the job of HR Manager is a little odd. The definition of statement purpose is "a Statement of Purpose is a sentence that you write, which states, in some detail, what you want to learn about in your research project."
As an HR Manager, what research will you do? Nothing!
There appears to be some over-zealous person at the top who is fond of using these fancy expressions. Nevertheless, when this fanciness overtakes the general approach, it creates a nonsensical situation. This could be one such situation.
I recommend you giving a relook while applying for the job. Generate more market information about the top boss. He may turn out to be whimsical. This is my guess.