What is Leia's first reaction when they destroyed all the TIE, when escaping the DS? She gives a big hug at Chewie.
Her character is not racist towards Wookies, she just do not like to be told what to do by Han and co, so she over reacts from time to time. It is perfectely understandable as she's a princess and is used to command and give orders.
Plus: it's funny.