Well it ain't surprising "ain't" is in the American College Dictionary - that's one of the dialects in which the word is current. Also in the one I speak.

Does pointing out that we all speak in one dialect or another count as putting anyone down? (Now, objecting to someone using a dialect different from the one we use - that might possibly count as an effort to put them down. In the case of ljc I somehow don't think it would work.)