Consider writing like an aggrieved Victorian aristocrat, or a protagonist in a Jane Austen novel.
My dearest Human resources department,
I am writing forthwith, to complain about the insinuation that I am to be considered intimidating with my extensive use of longer vocabulary. To wit, I should also like to raise a complaint of mine, such as is within my allowance, that there is an intimidating lack of long words used in workplace communications.
Good day,
Mean Elevator