I oppose PLAs simply because they violate the Equal Protection Clause of the Fourteenth Amendment by creating a special class of people, union workers, who have rights or benefits that others cannot have - in this case, the right to work, to be productive, and to be able to support one's family.
Why no one has challenged Deval Patrick on that is beyond me. I won’t go into the fact that the labor unions financially support people like Patrick and his ilk because of the favoritism they are able to buy (see corruption and greed in answer 1).
§ 1: All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the state wherein they reside. No state shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States; nor shall any state deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws.
The Equal Protection Clause of the Fourteenth Amendment of the U.S. Constitution (§ 1) prohibits states from denying any person within its jurisdiction the equal protection of the laws. In other words, the laws of a state must treat an individual in the same manner as others in similar conditions and circumstances. A violation would occur, for example, if a state prohibited an individual from entering into an employment contract because he or she was a member of a particular race. The equal protection clause is not intended to provide "equality" among individuals or classes but only "equal application" of the laws. The result, therefore, of a law is not relevant so long as there is no discrimination in its application. By denying states the ability to discriminate, the equal protection clause of the Constitution is crucial to the protection of civil rights.
~ From a Treatise on the Fourteenth Amendment