Technically, DEAC (former DETC) is a legitimate accrediting agency, but a lot of schools accredited by this agency are for-profit organizations. Also, there are questionable "non-profit" schools that are actually for-profit, such as the University of the People. The real non-profit schools are a minority.
Although most of these organizations are diploma mills, uninformed people often have a hard time recognizing them because they claim to be regionally-accredited schools.