Correct me if I'm mistaken, but fairly certain Wikipedia is not a professional organization. It's a resource, and if I am correct that any random person can edit and modify information on Wikipedia, hardly a reliable one, at that. I wouldn't cite it next time.
Edited to add: The actual letter you sent is excellent, btw. I shoulda remembered to write that the first time, too, and not just be a nit-picking editorial Nazi.