OK, I've commented about this before. This all started at the University of Michigan and the University of Virginia a few years back and is catching on like wildfire at other flagship public universities across the nation.
The theory is that graduates of the professional schools (medicine, dentistry, and law) will make tons of money after graduation so state tax payers should not be expected to subsidize the education of such professionals. Furthermore, the private universities have had no trouble filling all of the openings in their professional programs despite their high tuition rates.
Since generous educational loans are readily available for studens accepted to such professional programs I tend to buy into the arguement when put like this: "I'm a waitress supporting 2 kids by myself. That is the path I chose and I accept the economic impact upon my life without whining. I don't mind paying taxes to help kids get a high school education or even a college bachelors degree, but why should my taxes be used to support the education of doctors, dentists, and lawyers who will make way more money than I can ever hope to see.