Answer:
Holden hates people's ever-showing phoniness.
Explanation:
By this chapter in the novel, you can already identify most of the phony details that make Holden tick in irritation. One of these many details is the various compliments and unnecessary comments that appear throughout the novel. This is one of those.
Why does Ackley need to state it in such a "corny" way?
Or take Stradlater, as another example. Whenever he needs to ask for somebody to do him a favor, just like in this situation where he's asking Holden to write his composition for him, he feels the need to utilize compliments such as "hot-shot" or friendly nicknames like "buddyroo".