What Rubio said was: "If my kids went to sleep hungry every night and my country didn't give me an opportunity to feed them, there isn't a law, no matter how restrictive, that would prevent me from coming here."
To accuse him of advocation breaking the law, or to suggest that the statement is evidence that he does not respect the laws of U.S. is quite a stretch.
Unlike Obama's immigration fiat, Rubio has advocated changing the laws to make them (in his opinion) more just. Rubio is pointing out that sometimes civil laws are violated in order to abide by natural laws. Natural law requires that parents care for their children (cf. Blackstorne). Rubio is also pointing out that deporting those who enter the country through no fault of their own violates the Natural Law.
As Hadley Arkes argues in a great article here:
http://www.claremont.org/publications/crb/id.1875/article_detail.asp
Consider for example that proposition the Scottish philosopher Thomas Reid regarded as one of the truly "first principles" we draw from the logic of moral judgment itself, a principle I've restated in this way: that we do not hold people blameworthy or responsible for acts they were powerless to affect. That principle may cover a wide variety of things where people really had no causal powers over their condition or their acts and should not be held culpable. We may argue in different cases as to how powerless or incapable people actually were, but no one doubts the validity of the principle—
Or here where Charles Kesler argues about the validity as law that which passes the Congress.
http://www.claremont.org/publications/crb/id.1684/article_detail.asp
Can you have a bill, a single law, that is almost 3,000 pages long? In the old days, that would have constituted a whole code of laws. When our founders thought about law, they often thought along the lines of John Locke, who described law as a community's "settled standing rules, indifferent, and the same to all parties," emphasizing that to be legitimate a statute must be "received and allowed by common consent to be the standard of right and wrong, and the common measure to decide all controversies" between citizens.