How was Dill's comment on his aunt's alcoholism cynical.Harper Lee's To Kill a Mockingbird

In the Deep South there are colloquial meanings for some
words.  For instance,  the word to aggravate someone is used to
mean to irritate or rile that person whereas it does not have that meaning in other
geographical areas.  Since the author, Harper Lee, is herself a resident of southern
Alabama, there is a strong possibility that the use of the word
cynical by Aunt Alexandra in Chapter 22 is given a colloquial
meaning since it clearly does not mean its dictionary denotation of distrusting the
sincerity of the motives of others as it appears.  There, Aunt
Alexandra thinks that Dill tries to deflect his own wrongdoing by criticizing his aunt. 
Thus, to her, to make a person look bad in the face of one's own wrongdoing is
cynical.  What may be cynical, however, is Dill's suspicion of Aunt
Rachel's concern for him. This sentiment is expressed in Dill's remark, "she's just
seein' too many snakes in the closet," for with this observation Dill does express some
doubt about his aunt's motivations.